Abstract: This chapter describes the initial steps in the systematic review (SR) process. The committee recommends eight standards for ensuring a focus on clinical and patient decision making and designing SRs that minimize bias: (1) establishing the review team; (2) ensuring user and stakeholder input; (3) managing bias and conflict of interest (COI) for both the research team and (4) the users and stakeholders participating in the review; (5) formulating the research topic; (6) writing the review protocol; (7) providing for peer review of the protocol; and (8) making the protocol publicly available. The team that will conduct the review should include individuals with appropriate expertise and perspectives. Creating a mechanism for users and stakeholders—consumers, clinicians, payers, and members of clinical practice guideline panels—to provide input into the SR process at multiple levels helps to ensure that the SR is focused on real-world healthcare decisions. However, a process should be in place to reduce the risk of bias and COI from user and stakeholder input and in the SR team. The importance of the review questions and analytic framework in guiding the entire review process demands a rigorous approach to formulating the research questions and analytic framework. Requiring a research protocol that prespecifies the research methods at the outset of the SR process helps prevent the effects of bias.
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2
Standards for Initiating a
Systematic Review
Abstract: This chapter describes the initial steps in the systematic
review (SR) process. The committee recommends eight standards
for ensuring a focus on clinical and patient decision making and
designing SRs that minimize bias: (1) establishing the review
team; (2) ensuring user and stakeholder input; (3) managing bias
and conflict of interest (COI) for both the research team and (4) the
users and stakeholders participating in the review; (5) formulating
the research topic; (6) writing the review protocol; (7) provid-
ing for peer review of the protocol; and (8) making the protocol
publicly available. The team that will conduct the review should
include individuals with appropriate expertise and perspectives.
Creating a mechanism for users and stakeholders—consumers,
clinicians, payers, and members of clinical practice guideline pan-
els—to provide input into the SR process at multiple levels helps
to ensure that the SR is focused on real-world healthcare decisions.
However, a process should be in place to reduce the risk of bias
and COI from user and stakeholder input and in the SR team.
The importance of the review questions and analytic framework
in guiding the entire review process demands a rigorous approach
to formulating the research questions and analytic framework. Re-
quiring a research protocol that prespecifies the research methods
at the outset of the SR process helps prevent the effects of bias.
45
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46 FINDING WHAT WORKS IN HEALTH CARE
The initial steps in the systematic review (SR) process define
the focus of the complete review and influence its ultimate use in
making clinical decisions. Because SRs are conducted under varying
circumstances, the initial steps are expected to vary across differ-
ent reviews, although in all cases a review team should be estab -
lished, user and stakeholder input gathered, the topic refined, and
the review protocol formulated. Current practice falls far short of
recommended guidance1; well-designed, well-executed SRs are the
exception. At a workshop organized by the committee, representa-
tives from professional specialty societies, consumers, and payers
testified that existing SRs often fail to address questions that are
important for real-world healthcare decisions.2 In addition, many
SRs fail to develop comprehensive plans and protocols at the out -
set of the project, which may bias the reviews (Liberati et al., 2009;
Moher et al., 2007). As a consequence, the value of many SRs to
healthcare decisions makers is limited.
The committee recommends eight standards for ensuring a focus
on clinical and patient decision making and designing SRs that mini-
mize bias. The standards pertain to: establishing the review team,
ensuring user and stakeholder input, managing bias and conflict of
interest (COI) for both the research team and users and stakeholders,
formulating the research topic, writing the review protocol, provid-
ing for peer review of the protocol, and making the protocol publicly
available. Each standard includes a set of requirements composed
of elements of performance (Box 2-1). A standard is a process, action,
or procedure for performing SRs that is deemed essential to pro-
ducing scientifically valid, transparent, and reproducible results. A
standard may be supported by scientific evidence; by a reasonable
expectation that the standard helps to achieve the anticipated level
of quality in an SR; or by the broad acceptance of the practice in SRs.
Each standard includes elements of performance that the committee
deems essential.
1 Unless otherwise noted, expert guidance refers to the published methods of the
Evidence-based Practice Centers in the Agency for Healthcare and Research Quality
Effective Health Care Program, the Centre for Reviews and Dissemination (University
of York, UK), and the Cochrane Collaboration. The committee also consulted experts
at other organizations, including the Drug Effectiveness Review Project, the ECRI
Institute, the National Institute for Health and Clinical Excellence (UK), and several
Evidence-Based Practice Centers (with assistance from staff from the Agency for
Healthcare Research and Quality). See Appendix D for guidance.
2 On January 14, 2010, the committee held a workshop that included four panels
with representatives of organizations engaged in using and/or developing systematic
reviews, including SR experts, professional specialty societies, payers, and consumer
groups. See Appendix C for the complete workshop agenda.
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STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
ESTABLISHING THE REVIEW TEAM
The review team is composed of the individuals who will man-
age and conduct the review. The objective of organizing the review
team is to pull together a group of researchers as well as key users
and stakeholders who have the necessary skills and clinical content
knowledge to produce a high-quality SR. Many tasks in the SR
process should be performed by multiple individuals with a range
of expertise (e.g., searching for studies, understanding primary
study methods and SR methods, synthesizing findings, performing
meta-analysis). Perceptions of the review team’s trustworthiness
and knowledge of real-world decision making are also important
for the final product to be used confidently by patients and clini-
cians in healthcare decisions. The challenge is in identifying all of
the required areas of expertise and selecting individuals with these
skills who are neither conflicted nor biased and who are perceived
as trustworthy by the public.
This section of the chapter presents the committee’s recom-
mended standards for organizing the review team. It begins with
background on issues that are most salient to setting standards for
establishing the review team: the importance of a multidisciplinary
review team, the role of the team leader, and bias and COI. The ratio-
nale for the recommended standards follows. Subsequent sections
address standards for involving various users and stakeholders in
the SR process, formulating the topic of the SR, and developing the
SR protocol. The evidence base for these initial steps in the SR pro-
cess is sparse. The committee developed the standards by reviewing
existing expert guidance and weighing the alternatives according
to the committee’s agreed-on criteria, especially the importance of
improving the acceptability and patient-centeredness of publicly
funded SRs (see Chapter 1 for a full discussion of the criteria).
A Multidisciplinary Review Team
The review team should be capable of defining the clinical ques-
tion and performing the technical aspects of the review. It should
be multidisciplinary, with experts in SR methodology, including
risk of bias, study design, and data analysis; librarians or informa -
tion specialists trained in searching bibliographic databases for SRs;
and clinical content experts. Other relevant users and stakeholders
should be included as feasible (CRD, 2009; Higgins and Green, 2008;
Slutsky et al., 2010). A single member of the review team can have
multiple areas of expertise (e.g., SR methodology and quantitative
analysis). The size of the team will depend on the number and com-
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48 FINDING WHAT WORKS IN HEALTH CARE
BOX 2-1
Recommended Standards for Initiating
a Systematic Review
Standard 2.1 Establish a team with appropriate expertise and experi-
ence to conduct the systematic review
Required elements:
2.1.1 Include expertise in the pertinent clinical content areas
2.1.2 Include expertise in systematic review methods
2.1.3 Include expertise in searching for relevant evidence
2.1.4 Include expertise in quantitative methods
2.1.5 Include other expertise as appropriate
Standard 2.2 Manage bias and conflict of interest (COI) of the team
conducting the systematic review
Required elements:
2.2.1 Require each team member to disclose potential COI and
professional or intellectual bias
2.2.2 Exclude individuals with a clear financial conflict
2.2.3 Exclude individuals whose professional or intellectual bias
would diminish the credibility of the review in the eyes of the
intended users
Standard 2.3 Ensure user and stakeholder input as the review is de-
signed and conducted
Required element:
2.3.1 Protect the independence of the review team to make the
final decisions about the design, analysis, and reporting of
the review
Standard 2.4 Manage bias and COI for individuals providing input into
the systematic review
Required elements:
2.4.1 Require individuals to disclose potential COI and profes-
sional or intellectual bias
2.4.2 Exclude input from individuals whose COI or bias would di-
minish the credibility of the review in the eyes of the intended
users
Standard 2.5 Formulate the topic for the systematic review
Required elements:
2.5.1 Confirm the need for a new review
plexity of the question(s) being addressed. The number of individu-
als with a particular expertise needs to be carefully balanced so that
one group of experts is not overly influential. For example, review
teams that are too dominated by clinical content experts are more
likely to hold preconceived opinions related to the topic of the SR,
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STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
2.5.2 Develop an analytic framework that clearly lays out the chain
of logic that links the health intervention to the outcomes
of interest and defines the key clinical questions to be ad-
dressed by the systematic review
2.5.3 Use a standard format to articulate each clinical question of
interest
2.5.4 State the rationale for each clinical question
2.5.5 Refine each question based on user and stakeholder input
Standard 2.6 Develop a systematic review protocol
Required elements:
2.6.1 Describe the context and rationale for the review from both
a decision-making and research perspective
2.6.2 Describe the study screening and selection criteria (inclu-
sion/exclusion criteria)
2.6.3 Describe precisely which outcome measures, time points,
interventions, and comparison groups will be addressed
2.6.4 Describe the search strategy for identifying relevant evidence
2.6.5 Describe the procedures for study selection
2.6.6 Describe the data extraction strategy
2.6.7 Describe the process for identifying and resolving disagree-
ment between researchers in study selection and data ex-
traction decisions
2.6.8 Describe the approach to critically appraising individual
studies
2.6.9 Describe the method for evaluating the body of evidence, in-
cluding the quantitative and qualitative synthesis strategies
2.6.10 Describe and justify any planned analyses of differen-
tial treatment effects according to patient subgroups,
how an intervention is delivered, or how an outcome is
measured
2.6.11 Describe the proposed timetable for conducting the review
Standard 2.7 Submit the protocol for peer review
Required element:
2.7.1 Provide a public comment period for the protocol and pub-
licly report on disposition of comments
Standard 2.8 Make the final protocol publicly available, and add any
amendments to the protocol in a timely fashion
spend less time conducting the review, and produce lower quality
SRs (Oxman and Guyatt, 1993).
Research examining dynamics in clinical practice guideline
(CPG) groups suggests that the use of multidisciplinary groups is
likely to lead to more objective decision making (Fretheim et al.,
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50 FINDING WHAT WORKS IN HEALTH CARE
2006a; Hutchings and Raine, 2006; Murphy et al., 1998; Shrier et al.,
2008). These studies are relevant to SR teams because both the guide-
line development and the SR processes involve group dynamics and
subjective judgments (Shrier et al., 2008). Murphy and colleagues
(1998), for example, conducted an SR that compared judgments
made by multi- versus single-disciplinary clinical guideline groups.
They found that decision-making teams with diverse members con-
sider a wider variety of alternatives and allow for more creative
decision making compared with single disciplinary groups. In a
2006 update, Hutchings and Raine identified 22 studies examining
the impact of group members’ specialty or profession on group deci-
sion making and found similar results (Hutchings and Raine, 2006).
Guideline groups dominated by medical specialists were more likely
to recommend techniques that involve their specialty than groups
with more diverse expertise. Fretheim and colleagues (2006a) iden -
tified six additional studies that also indicated medical specialists
have a lower threshold for recommending techniques that involve
their specialty. Based on this research, a guideline team considering
interventions to prevent hip fracture in the elderly, for example,
should include family physicians, internists, orthopedists, social
workers, and others likely to work with the patient population at
risk.
The Team Leader
Minimal research and guidance have been done on the leader-
ship of SR teams. The team leader’s most important qualifications
are knowledge and experience in proper implementation of an SR
protocol, and open-mindedness about the topics to be addressed in
the review. The leader should also have a detailed understanding of
the scope of work and be skilled at overseeing team discussions and
meetings. SR teams rely on the team leader to act as the facilitator of
group decision making (Fretheim et al., 2006b).
The SR team leader needs to be skilled at eliciting meaningful
involvement of all team members in the SR process. A well-balanced
and effective multidisciplinary SR team is one where every team
member contributes (Fretheim et al., 2006b). The Institute of Medi-
cine (IOM) directs individuals serving on its committees to be open
to new ideas and willing to learn from one another (IOM, 2005). The
role of the leader as facilitator is particularly important because SR
team members vary in professional roles and depth of knowledge
(Murphy et al., 1998). Pagliari and Grimshaw (2002) observed a mul-
tidisciplinary committee and found that the chair made the largest
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STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
contributions to group discussion and was pivotal in ensuring inclu-
sion of the views of all parties. Team members with less specializa-
tion, such as primary care physicians and nurses, tended to be less
active in the group discussion compared with medical specialists.
Bias and Conflicts of Interest
Minimizing bias and COI in the review team is important to
ensure the acceptability, credibility, and scientific rigor of the SR.3 A
recent IOM report, Conflict of Interest in Medical Research, Education,
and Practice, defined COI as “a set of circumstances that creates a risk
that professional judgment or actions regarding a primary interest
will be unduly influenced by a secondary interest” (IOM, 2009a,
p. 46). Disclosure of individual financial, business, and professional
interests is the established method of dealing with researchers’ COI
(IOM, 2009a). A recent survey of high-impact medical journals found
that 89 percent required authors to disclose COIs (Blum et al., 2009).
The International Committee of Medical Journal Editors (ICMJE)
recently created a universal disclosure form for all journals that
are members of ICMJE to facilitate the disclosure process (Box 2-2)
(Drazen et al., 2009, 2010; ICMJE, 2010). Leading guidance from pro-
ducers of SRs also requires disclosure of competing interest (CRD,
2009; Higgins and Green, 2008; Whitlock et al., 2010). The premise
of disclosure policies is that reporting transparency allows readers
to judge whether these conflicts may have influenced the results of
the research. However, many authors fail to fully disclose their COI
despite these disclosure policies (Chimonas et al., 2011; McPartland,
2009; Roundtree et al., 2008). Many journals only require disclo-
sure of financial conflicts, and do not require researchers to disclose
intellectual and professional biases that may be similarly influential
(Blum et al., 2009).
Because of the importance of preventing bias from undermin-
ing the integrity of biomedical research, a move has been made to
strengthen COI policies. The National Institutes of Health (NIH),
for example, recently announced it is revising its policy for manag-
ing financial COI in biomedical research to improve compliance,
strengthen oversight, and expand transparency in this area (Rockey
and Collins, 2010). There is also a push toward defining COI to
include potential biases beyond financial conflicts. The new ICMJE
policy requires that authors disclose “any other relationships or
3 Elsewhere in this report, the term “bias” is used to refer to bias in reporting and
publication (see Chapter 3).
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52 FINDING WHAT WORKS IN HEALTH CARE
BOX 2-2
International Committee of Medical Journal Editors
Types of Conflict-of-Interest Disclosures
• Associations with commercial entities that provided support for the work
reported in the submitted manuscript. Should include both resources
received directly and indirectly (via your institution) that enabled the
author to complete the work.
• Associations with commercial entities that could be viewed as having an
interest in the general area of the submitted manuscript.
• Other relationships or activities that readers could perceive to have
influenced, or that give the appearance of potentially influencing, what
the author wrote in the submitted work.
SOURCE: ICMJE (2010).
activities that readers could perceive to influence, or that give the
appearance of potentially influencing” the research, such as per-
sonal, professional, political, institutional, religious, or other associa-
tions (Drazen et al., 2009, 2010, p. 268). The Cochrane Collaboration
also requires members of the review team to disclose “competing
interests that they judge relevant” (The Cochrane Collaboration,
2006). Similarly, the Patient-Centered Outcomes Research Institute
(PCORI), created by the 2010 Patient Protection and Affordable Care
Act, will require individuals serving on the Board of Governors,
the methodology committee, and expert advisory panels to disclose
both financial and personal associations.4
Secondary interests, such as the pursuit of professional advance-
ment, future funding opportunities, and recognition, and the desire
to do favors for friends and colleagues, are also important potential
conflicts (IOM, 2009a). Moreover, mere disclosure of a conflict does
not resolve or eliminate it. Review teams should also evaluate and
act on the disclosed information. Eliminating the relationship, fur-
ther disclosure, or restricting the participation of a researcher with
COI may be necessary. Bias and COI may also be minimized by
creating review teams that are balanced across relevant expertise
and perspectives as well as competing interests (IOM, 2009a). The
Cochrane Collaboration, for example, requires that if a member of
4 The Patient Protection and Affordable Care Act, Public Law 111-148, 111th Cong.,
Subtitle D, § 6301 (March 23, 2010).
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STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
the review team is an author of a study that is potentially eligible
for the SR, there must be other members of the review team who
were not involved in that study. In addition, if an SR is conducted by
individuals employed by a pharmaceutical or device company that
relates to the products of that company, the review team must be
multidisciplinary, with the majority of the members not employed
by the relevant company. Individuals with a direct financial interest
in an intervention may not be a member of the review team conduct-
ing an SR of that intervention (The Cochrane Collaboration, 2006).
Efforts to prevent COI in health research should focus on not only
whether COI actually biased an individual, but also whether COI
has the potential for bias or appearance of bias (IOM, 2009a).
RECOMMENDED STANDARDS FOR
ORGANIZING THE REVIEW TEAM
The committee recommends two standards for organizing the review
team:
Standard 2.1—Establish a team with appropriate expertise and
experience to conduct the systematic review
Required elements:
2.1.1 Include expertise in pertinent clinical content areas
2.1.2 Include expertise in systematic review methods
2.1.3 Include expertise in searching for relevant evidence
2.1.4 Include expertise in quantitative methods
2.1.5 Include other expertise as appropriate
Standard 2.2—Manage bias and conflict of interest (COI) of
the team conducting the systematic review
Required elements:
2.2.1 Require each team member to disclose potential
COI and professional or intellectual bias
2.2.2 Exclude individuals with a clear financial conflict
2.2.3 Exclude individuals whose professional or intel-
lectual bias would diminish the credibility of the
review in the eyes of the intended users
Rationale
The team conducting the SR should include individuals skilled in
group facilitation who can work effectively with a multidisciplinary
review team, an information specialist, and individuals skilled in
project management, writing, and editing (Fretheim et al., 2006a).
In addition, at least one methodologist with formal training and
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54 FINDING WHAT WORKS IN HEALTH CARE
experience in conducting SRs should be on the team. Performance
of SRs, like any form of biomedical research, requires education
and training, including hands-on training (IOM, 2008). Each of the
steps in conducting an SR should be, as much as possible, evidence
based. Methodologists (e.g., epidemiologists, biostatisticians, health
services researchers) perform much of the research on the conduct of
SRs and are likely to stay up-to-date with the literature on methods.
Their expertise includes decisions about study design and potential
for bias and influence on findings, methods to minimize bias in the
SR, qualitative synthesis, quantitative methods, and issues related
to data collection and data management.
For SRs of comparative effectiveness research (CER), the team
should include people with expertise in patient care and clinical
decision making. In addition, as discussed in the following section,
the team should have a clear and transparent process in place for
obtaining input from consumers and other users and stakeholders
to ensure that the review is relevant to patient concerns and useful
for healthcare decisions. Single individuals might provide more
than one area of required expertise. The exact composition of the
review team should be determined by the clinical questions and
context of the SR. The committee’s standard is consistent with guid-
ance from the Agency for Healthcare Research and Quality (AHRQ)
Evidence-based Practice Center (EPC), the United Kingdom’s Centre
for Reviews and Dissemination (CRD), and the Cochrane Collabora-
tion (CRD, 2009; Higgins and Green, 2008; Slutsky et al., 2010). It is also
integral to the committee’s criteria of scientific rigor by ensuring the
review team has the skills necessary to conduct a high-quality SR.
The committee believes that minimizing COI and bias is criti-
cal to credibility and scientific rigor. Disclosure alone is insufficient.
Individuals should be excluded from the review team if their partici-
pation would diminish public perception of the independence and
integrity of the review. Individuals should be excluded for financial
conflicts as well as for professional or intellectual bias. This is not
to say that knowledgeable experts cannot participate. For example,
it may be possible to include individual orthopedists in reviews of
the efficacy of back surgery depending on the individual’s specific
employment, sources of income, publications, and public image.
Other orthopedists may have to be excluded if they may benefit
from the conclusions of the SR or may undermine the credibility
of the SR. This is consistent with the recent IOM recommendations
(IOM, 2009a). However, this standard is stricter than all of the major
organizations’ guidance on this topic, which emphasize disclosure of
professional or intellectual bias, rather than requiring the exclusion of
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STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
individuals with this type of competing interest (CRD, 2009; Higgins
and Green, 2008; Slutsky et al., 2010). In addition, because SRs may
take a year or more to produce, the SR team members should update
their financial COI and personal biases at regular intervals.
ENSURING USER AND STAKEHOLDER INPUT
The target audience for SRs of CER include consumers, patients,
and their caregivers; clinicians; payers; policy makers; private
industry; organizations that develop quality indicators; SR spon -
sors; guideline developers; and others involved in “deciding what
medical therapies and practice are approved, marketed, promoted,
reimbursed, rewarded, or chosen by patients” (Atkins, 2007, p. S16).
The purpose of CER, including SRs of CER, is to “assist consum-
ers, clinicians, purchasers, and policy makers to make informed
decisions that will improve health care at both the individual and
populations levels” (IOM, 2009b, p. 41). Creating a clear and explicit
mechanism for users and stakeholders to provide input into the SR
process at multiple levels, beginning with formulating the research
questions and analytic framework, is essential to achieving this pur-
pose. A broad range of views should be considered in deciding
on the scope of the SR. Often the organization(s) that nominate or
sponsor an SR may be interested in specific populations, interven-
tions, comparisons, and outcomes. Other users and stakeholders
may bring a different perspective on the appropriate scope for a
review. Research suggests that involving decision makers directly
increases the relevance of SRs to decision making (Lavis et al., 2005;
Schünemann et al., 2006).
Some SR teams convene formal advisory panels with representa-
tion from relevant user and stakeholder groups to obtain their input.
Other SR teams include users and stakeholders on the review team,
or use focus groups or conduct structured interviews with individu-
als to elicit input. Whichever model is used, the review team must
include a skilled facilitator who can work effectively with consum-
ers and other users and stakeholders to develop the questions and
scope for the review. Users and stakeholders may have conflicting
interests or very different ideas about what outcomes are relevant, as
may other members of the review team, to the point that reconciling
all of the different perspectives might be very challenging.
AHRQ has announced it will spend $10 million on establishing
a Community Forum for CER to engage users and stakeholders
formally, and to expand and standardize public involvement in the
entire Effective Health Care Program (AHRQ, 2010). Funds will be
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70 FINDING WHAT WORKS IN HEALTH CARE
1
2
Enteral
supplement
nutrition
(type, dose,
Geriatric Improved energy,
Improved Healing Mortality
etc.)
patients supply to, and 4
nutritional of the
with microcirculation
status bedsore Quality of life
bedsores 3 of the wound
Diarrhea,
other adverse
effects
FIGURE 2-1 Analytic framework for a new enteral supplement to heal
Figure 2-1.eps
bedsores.
SOURCE: Helfand and Balshem (2010).
and health outcomes (e.g., myocardial infarction and strokes). It can
also help clarify the researchers’ implicit beliefs about the benefits
of a healthcare intervention, such as quality of life, morbidity, and
mortality (Helfand and Balshem, 2010). It increases the likelihood
that all contributing elements in the causal chain will be examined
and evaluated. However, the analytic framework diagram may need
to evolve to accurately represent SRs of CER that compare alterna-
tive treatments and interventions.
Figure 2-1 shows an analytic framework for evaluating studies
of a new enteral supplement to heal bedsores (Helfand and Balshem,
2010). On the left side of the analytic framework is the population of
interest: geriatric patients with bedsores. Moving from left to right
across the framework is the intervention (enteral supplement nutri-
tion), intermediate outcomes (improved nutritional status, improved
energy/blood supply to the wound, and healing of the bedsore),
and final health outcomes of interest (reduction in mortality, quality
of life). The lines with arrows represent the researchers’ questions
that the evidence must answer at each phase of the review. The
dotted lines indicate that the association between the intermediate
outcomes and final health outcomes are unproven, and need to be
linked by evaluating several bodies of evidence. The squiggly line
denotes the question that addresses the harms of the intervention
(e.g., diarrhea or other adverse effects). In this example, the lines and
arrows represent the following key research questions:
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STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
Line 1 Does enteral supplementation improve mortality and
quality of life?
Line 2 Does enteral supplementation improve wound healing?
Line 3 How frequent and severe are side effects such as
diarrhea?
Line 4 Is wound healing associated with improved survival
and quality of life?
Evidence that directly links the intervention to the final health
outcome is the most influential (Arrow 1). Arrows 2 and 4 link the
treatments to the final outcomes indirectly: from treatment to an
intermediate outcome, and then, separately, from the intermediate
outcome to the final health outcomes. The nutritional status and
improved energy/blood supply to the wound are only important
outcomes if they are in the causal pathway to improved healing,
reduced mortality, and a better quality of life. The analytic frame -
work does not have corresponding arrows to these intermediate
outcomes because studies measuring these outcomes would only be
included in the SR if they linked the intermediate outcome to heal-
ing, mortality, or quality of life.
RECOMMENDED STANDARDS FOR
FORMULATING THE TOPIC
The importance of the research questions and analytic frame-
work in determining the entire review process demands a rigorous
approach to topic formulation. The committee recommends the fol-
lowing standard:
Standard 2.5—Formulate the topic for the systematic review
Required elements:
2.5.1 Confirm the need for a new review
2.5.2 Develop an analytic framework that clearly lays
out the chain of logic that links the health inter-
vention to the outcomes of interest and defines
the key clinical questions to be addressed by the
systematic review
2.5.3 Use a standard format to articulate each clinical
question of interest
2.5.4 State the rationale for each clinical question
2.5.5 Refine each question based on user and stake-
holder input
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72 FINDING WHAT WORKS IN HEALTH CARE
Rationale
SRs of CER should focus on specific research questions using
a structured format (e.g., PICO[TS]), an analytic framework, and
a clear rationale for the research question. Expert guidance recom-
mends using the PICO(TS) acronym to articulate research ques-
tions (CRD, 2009; Higgins and Green, 2008; Whitlock et al., 2010).
Developing an analytic framework is required by the EPCs to illus -
trate the chain of logic underlying the research questions (AHRQ,
2007; Helfand and Balshem, 2010; IOM, 2008). Using a structured
approach and analytic framework also improves the scientific rigor
and transparency of the review by requiring the review team to
clearly articulate the clinical questions and basic assumptions in
the SR.
The AHRQ EPC program, CRD, and the Cochrane Collaboration
all have mechanisms for ensuring that new reviews cover novel and
important topics. AHRQ, for example, specifically requires that top-
ics have strong potential for improving health outcomes (Whitlock
et al., 2010). CRD recommends that researchers undertaking reviews
first search for existing or ongoing reviews and evaluate the quality
of any reviews on similar topics (CRD, 2009). The Cochrane Col-
laboration review groups require approval by the “coordinating
editor” (editor in chief) of the relevant review group for new SRs
(Higgins and Green, 2008). Confirming the need for a new review
is consistent with the committee’s criterion of efficiency because it
prevents the burden and cost of conducting an unnecessary, duplica-
tive SR (unless the “duplication” is considered necessary to improve
on earlier efforts). If the SR registries now in development become
fully operational, this requirement will become much easier for the
review team to achieve in the near future (CRD, 2010; HHS, 2010;
Joanna Briggs Institute, 2010; NPAF, 2011; PIPC, 2011).
DEVELOPING THE SYSTEMATIC REVIEW PROTOCOL
The SR protocol is a detailed description of the objectives and
methods of the review (CRD, 2009; Higgins and Green, 2008; Liberati
et al., 2009). The protocol should include information regarding the
context and rationale for the review, primary outcomes of interest,
search strategy, inclusion/exclusion criteria, data synthesis strategy,
and other aspects of the research plan. The major challenge to writ -
ing a comprehensive research protocol is accurately specifying the
research questions and methods before the study begins. Develop-
ing the protocol is an iterative process that requires communication
with users and stakeholders, input from the general public, and a
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STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
preliminary review of the literature before all of the components
of the protocol are finalized (CRD, 2009). Researchers’ decisions to
undertake an SR may be influenced by prior knowledge of results
of available studies. The inclusion of multiple perspectives on the
review team and gathering user and stakeholder input helps pre-
vent choices in the protocol that are based on such prior knowledge.
The use of protocols in SRs is increasing, but is still not stan-
dard practice. A survey of SRs indexed in MEDLINE in November,
2004 found that 46 percent of the reviews reported using a protocol
(Moher et al., 2007), a significant rise from only 7 percent of reviews
in an earlier survey (Sacks et al., 1987).
Publication of the Protocol
A protocol should be made publicly available at the start of an
SR in order to prevent the effects of author bias, allow feedback at
an early stage in the SR, and tell readers of the review about protocol
changes that occur as the SR develops. It also gives the public the
chance to examine how well the SR team has used input from con-
sumers, clinicians, and other experts to develop the questions and
PICO(TS) the review will address. In addition, a publicly available
protocol has the benefit that other researchers can identify ongoing
reviews, and thus avoids unnecessary duplication and encourages
collaboration. This transparency may provide an opportunity for
methodological and other research (see Chapter 6) (CRD, 2010).
One of the most efficient ways to publish protocols is through an
SR protocol electronic registration. However, more than 80 percent
of SRs are conducted by organizations that do not have existing
registries (CRD, 2010). The Cochrane Collaboration and AHRQ have
created their own infrastructure for publishing protocols (Higgins
and Green, 2008; Slutsky et al., 2010). Review teams conducting SRs
funded through PCORI9 will also be required to post research proto-
cols on a government website at the outset of the SR process.
Several electronic registries under development intend to pub-
lish all SR protocols, regardless of the funding source (CRD, 2010;
Joanna Briggs Institute, 2010). CRD is developing an international
registry of ongoing health-related SRs that will be open to all pro-
spective registrations and will offer free public access for electronic
searching. Each research protocol will be assigned a unique identifi-
9 The Patient Protection and Affordable Care Act, Public Law 111-148, 111th Cong.,
Subtitle D, § 6301 (March 23, 2010).
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74 FINDING WHAT WORKS IN HEALTH CARE
cation number, and an audit trail of amendments will be part of each
protocol’s record. The protocol records will also link to the resulting
publication. The Preferred Reporting Items for Systematic Reviews
and Meta-Analyses (PRISMA) Statement reflects the growing rec-
ognition of the importance of prospective registration of protocols,
and requires that published SRs indicate whether a review protocol
exists and if and where it can accessed (e.g., web address), and the
registration information and number (Liberati et al., 2009).
Amendments to the Protocol
Often the review team needs to make amendments to a protocol
after the start of the review that result from the researchers’ improved
understanding of the research questions or the availability of pertinent
evidence (CRD, 2009; Higgins and Green, 2008; Liberati et al., 2009).
Common amendments include extending the period of the search to
include older or newer studies, broadening eligibility criteria, and
adding new analyses suggested by the primary analysis (Liberati
et al., 2009). Researchers should document such amendments with
an explanation for the change in the protocol and completed review
(CRD, 2009; Higgins and Green, 2008; Liberati et al., 2009).
In general, researchers should not modify the protocol based on
knowledge of the results of analyses. This has the potential to bias
the SR, for example, if the SR omits a prespecified comparison when
the data indicate that an intervention is more or less effective than
the retained comparisons. Similar problems occur when researchers
modify the protocol by adding or deleting certain study designs or
outcome measures, or change the search strategy based on prior
knowledge of the data. Researchers may be motivated to delete
an outcome when its results do not match the results of the other
outcome measures (Silagy et al., 2002), or to add an outcome that
had not been prespecified. Publishing the protocol and amendments
allows readers to track the changes and judge whether an amend-
ment has biased the review. The final SR report should also identify
those analyses that were prespecified and those that were not, and
any analyses requested by peer reviewers (see Chapter 5).
RECOMMENDED STANDARDS FOR DEVELOPING
THE SYSTEMATIC REVIEW PROTOCOL
The committee recommends three standards related to the SR
protocol:
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75
STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
Standard 2.6—Develop a systematic review protocol
Required elements:
2.6.1 Describe the context and rationale for the re-
view from both a decision-making and research
perspective
2.6.2 Describe the study screening and selection criteria
(inclusion/exclusion criteria)
2.6.3 Describe precisely which outcome measures, time
points, interventions, and comparison groups will
be addressed
2.6.4 Describe the search strategy for identifying rel-
evant evidence
2.6.5 Describe the procedures for study selection
2.6.6 Describe the data extraction strategy
2.6.7 Describe the process for identifying and resolving
disagreement between researchers in study selec-
tion and data extraction decisions
2.6.8 Describe the approach to critically appraising
individual studies
2.6.9 Describe the method for evaluating the body of
evidence, including the quantitative and qualita-
tive synthesis strategy
2.6.10 Describe and justify any planned analyses of dif-
ferential treatment effects according to patient
subgroups, how an intervention is delivered, or
how an outcome is measured
2.6.11 Describe the proposed timetable for conducting
the review
Standard 2.7—Submit the protocol for peer review
Required element:
2.7.1 Provide a public comment period for the protocol
and publicly report on disposition of comments
Standard 2.8—Make the final protocol publicly available, and
add any amendments to the protocol in a timely fashion
Rationale
The majority of these required elements are consistent with
leading guidance, and ensure that the protocol provides a detailed
description of the objectives and methods of the review (AHRQ,
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76 FINDING WHAT WORKS IN HEALTH CARE
2009; CRD, 2009; Higgins and Green, 2008).10 The committee added
the requirement to identify and justify planned subgroup analy-
ses to examine whether treatment effects vary according to patient
group, the method of providing the intervention, or the approach to
measuring an outcome, because evidence on variability in treatment
effects across subpopulations is key to directing interventions to the
most appropriate populations. The legislation establishing PCORI
requires that “research shall be designed, as appropriate, to take into
account the potential for differences in the effectiveness of health-
care treatments, services, and items as used with various subpopula-
tions, such as racial and ethnic minorities, women, age, and groups
of individuals with different comorbidities, genetic and molecular
subtypes, or quality of life preferences.”11 The protocol should state
a hypothesis that justifies the planned subgroup analyses, including
the direction of the suspected subgroup effects, to reduce the pos-
sibility of identifying false subgroup effects. The subgroup analyses
should also be limited to a small number of hypothesized effects
(Sun et al., 2010). The committee also added the requirement that the
protocol include the proposed timetable for conducting the review
because this improves the transparency, efficiency, and timeliness of
publicly funded SRs.
The draft protocol should be reviewed by clinical and method-
ological experts as well as relevant users and stakeholders identified
by the review team and sponsor. For publicly funded reviews, the
public should also have the opportunity to comment on the protocol
to improve the acceptability and transparency of the SR process. The
review team should be responsive to peer reviewers and public com-
ments and publicly report on the disposition of the comments. The
review team need not provide a public response to every question;
it can group questions into general topic areas for response. The
period for peer review and public comment should be specified so
that the review process does not delay the entire SR process.
Cochrane requires peer review of protocols (Higgins and Green,
2008). The EPC program requires that the SR research questions and
protocol be available for public comment (Whitlock et al., 2010).12
All of the leading guidance requires that the final protocol be pub-
10 The elements are all discussed in more detail in Chapters 3 through 5.
11 The Patient Protection and Affordable Care Act, Public Law 111-148, 111th Cong.,
Subtitle D, § 6301(d)(2)(D) (March 23, 2010).
12 Information on making the protocol public comes from Mark Helfand, Director,
Oregon Evidence-Based Practice Center, Professor of Medicine and Medical Infor-
matics and Clinical Epidemiology, Oregon Health and Science University, Portland,
Oregon.
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STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
licly available (CRD, 2009; Higgins and Green, 2008; Whitlock et al.,
2010).
REFERENCES
AHRQ (Agency for Healthcare Research and Quality). 2007. Methods reference guide
for effectiveness and comparative effectiveness reviews, Version 1.0. Rockville, MD:
AHRQ.
AHRQ. 2009. AHRQ Evidence-based Practice Centers partner’s guide. Rockville, MD:
AHRQ.
AHRQ. 2010. Reinvestment Act investments in comparative effectiveness research for a
citizen forum. Rockville, MD: AHRQ. http://ftp.ahrq.gov/fund/cerfactsheets/
cerfsforum.htm (accessed August 30, 2010).
Andejeski, Y., E. S. Breslau, E. Hart, N. Lythcott, L. Alexander, I. Rich, I. Bisceglio,
H. S. Smith, and F. M. Visco. 2002. Benefits and drawbacks of including con-
sumer reviewers in the scientific merit review of breast cancer research. Journal
of Women’s Health & Gender-Based Medicine 11(2):119–136.
Atkins, D. 2007. Creating and synthesizing evidence with decision makers in mind:
Integrating evidence from clinical trials and other study designs. Medical Care
45(10 Suppl 2):S16–S22.
Ayanian, J. Z., M. B. Landrum, S. T. Normand, E. Guadagnoli, and B. J. McNeil. 1998.
Rating the appropriateness of coronary angiography—Do practicing physicians
agree with an expert panel and with each other? New England Journal of Medicine
338(26):1896–1904.
Bastian, H. 2005. Consumer and researcher collaboration in trials: Filling the gaps.
Clinical Trials 2(1):3–4.
Blum, J. A., K. Freeman, R. C. Dart, and R. J. Cooper. 2009. Requirements and defi-
nitions in conflict of interest policies of medical journals. JAMA 302(20):2230–
2234.
Boote, J., R. Telford, and C. Cooper. 2002. Consumer involvement in health research:
A review and research agenda. Health Policy 61(2):213–236.
Cherkin, D. C., R. A. Deyo, M. Battié, J. Street, and W. Barlow. 1998. A comparison
of physical therapy, chiropractic manipulation, and provision of an educational
booklet for the treatment of patients with low back pain. New England Journal of
Medicine 339(15):1021–1029.
Chimonas, S., Z. Frosch, and D. J. Rothman. 2011. From disclosure to transparency:
The use of company payment data. Archives of Internal Medicine 171(1):81–86.
The Cochrane Collaboration. 2006. Commercial sponsorship and The Cochrane Collabo-
ration. http://www.cochrane.org/about-us/commercial-sponsorship (accessed
January 11, 2011).
Counsell, C. 1997. Formulating questions and locating primary studies for inclusion
in systematic reviews. Annals of Internal Medicine 127(5):380–387.
CRD (Centre for Reviews and Dissemination). 2009. Systematic reviews: CRD’s guidance
for undertaking reviews in health care. York, UK: York Publishing Services, Ltd.
CRD. 2010. Register of ongoing systematic reviews. http://www.york.ac.uk/inst/crd/
projects/register.htm (accessed June 17, 2010).
Drazen, J., M. B. Van Der Weyden, P. Sahni, J. Rosenberg, A. Marusic, C. Laine, S.
Kotzin, R. Horton, P. C. Hebert, C. Haug, F. Godlee, F. A. Frozelle, P. W. Leeuw,
and C. D. DeAngelis. 2009. Uniform format for disclosure of competing interests
in ICMJE journals. New England Journal of Medicine 361(19):1896–1897.
OCR for page 45
78 FINDING WHAT WORKS IN HEALTH CARE
Drazen, J. M., P. W. de Leeuw, C. Laine, C. D. Mulrow, C. D. DeAngelis, F. A. Frizelle,
F. Godlee, C. Haug, P. C. Hébert, A. James, S. Kotzin, A. Marusic, H. Reyes, J.
Rosenberg, P. Sahni, M. B. Van Der Weyden, and G. Zhaori. 2010. Toward more
uniform conflict disclosures: The updated ICMJE conflict of interest reporting
form. Annals of Internal Medicine 153(4):268–269.
Entwistle, V. A., M. J. Renfrew, S. Yearley, J. Forrester, and T. Lamont. 1998. Lay per-
spectives: Advantages for health research. BMJ 316(7129):463–466.
Fretheim, A., H. J. Schünemann, and A. D. Oxman. 2006a. Improving the use of re-
search evidence in guideline development: Group composition and consultation
process. Health Research Policy and Systems 4:15.
Fretheim, A., H. J. Schünemann, and A. D. Oxman. 2006b. Improving the use of
research evidence in guideline development: Group processes. Health Research
Policy and Systems 4:17.
Guyatt, G., E. A. Akl, J. Hirsh, C. Kearon, M. Crowther, D. Gutterman, S. Z. Lewis,
I. Nathanson, R. Jaeschke, and H. Schünemann. 2010. The vexing problem of
guidelines and conflict of interest: A potential solution. Annals of Internal Medi-
cine 152(11):738–741.
Harris, R. P., M. Helfand, S. H. Woolf, K. N. Lohr, C. D. Mulrow, S. M. Teutsch,
D. Atkins, and Methods Work Group Third U. S. Preventive Services Task
Force. 2001. Current methods of the U.S. Preventive Services Task Force:
A review of the process. American Journal of Preventive Medicine 20(Suppl 3):
21–35.
Helfand, M., and H. Balshem. 2010. AHRQ Series Paper 2: Principles for develop -
ing guidance: AHRQ and the Effective Health-Care Program. Journal of Clinical
Epidemiology 63(5):484–490.
HHS (Department of Health and Human Services). 2010. Request for Information
on development of an inventory of comparative effectiveness research. Federal
Register 75 (137):41867–41868.
Higgins, J. P. T., and S. Green, eds. 2008. Cochrane handbook for systematic reviews of
interventions. Chichester, UK: John Wiley & Sons.
Hutchings, A., and R. Raine. 2006. A systematic review of factors affecting the judg -
ments produced by formal consensus development methods in health care.
Journal of Health Services Research & Policy 11(3):172–179.
ICMJE (International Committee of Medical Journal Editors). 2007. Sponsorship, au-
thorship, and accountability. http://www.icmje.org/update_sponsor.html (ac-
cessed September 8, 2010).
ICMJE. 2010. ICMJE uniform disclosure form for potential conflicts of interest. http://
www.icmje.org/coi_disclosure.pdf (accessed January 11, 2011).
IOM (Institute of Medicine). 2005. Getting to know the committee process. Washington,
DC: The National Academies Press.
IOM. 2008. Knowing what works in health care: A roadmap for the nation. Edited by
J. Eden, B. Wheatley, B. McNeil, and H. Sox. Washington, DC: The National
Academies Press.
IOM. 2009a. Conflict of interest in medical research, education, and practice . Edited by B.
Lo and M. Field. Washington, DC: The National Academies Press.
IOM. 2009b. Initial national priorities for comparative effectiveness research . Washington,
DC: The National Academies Press.
Joanna Briggs Institute. 2010. Protocols and works in progress. Adelaide, Australia: The
Joanna Briggs Institute. http://www.joannabriggs.edu.au/pubs/systematic_
reviews_prot.php (accessed June 17, 2010).
OCR for page 45
79
STANDARDS FOR INITIATING A SYSTEMATIC REVIEW
Kahan, J. P., R. E. Park, L. L. Leape, S. J. Bernstein, L. H. Hilborne, L. Parker, C. J.
Kamberg, D. J. Ballard, and R. H. Brooke. 1996. Variations in specialty in physi -
cian ratings of the appropriateness and necessity of indications for procedures.
Medical Care 34(6):512–523.
KDIGO (Kidney Disease: Improving Global Outcomes). 2010. Clinical practice
guidelines. http://www.kdigo.org/clinical_practice_guidelines/guideline_
development_process.php (accessed July 16, 2010).
Lavis, J., H. Davies, A. Oxman, J. L. Denis, K. Golden-Biddle, and E. Ferlie. 2005.
Towards systematic reviews that inform health care management and policy-
making. Journal of Health Services Research & Policy 10(Suppl 1):35–48.
Liberati, A., D. G. Altman, J. Tetzlaff, C. Mulrow, P. C. Gotzsche, J. Ioannidis, M.
Clarke, P. J. Devereaux, J. Kleijnen, and D. Moher. 2009. The PRISMA statement
for reporting systematic reviews and meta-analyses of studies that evaluate
health care interventions: Explanation and elaboration. Annals of Internal Medi-
cine 151(4):W1–W30.
McPartland, J. M. 2009. Obesity, the endocannabinoid system, and bias arising from
pharmaceutical sponsorship. PLoS One 4(3):e5092.
Moher, D., J. Tetzlaff, A. C. Tricco, M. Sampson, and D. G. Altman. 2007. Epidemiol -
ogy and reporting characteristics of systematic reviews. PLoS Medicine 4(3):
447–455.
Mulrow, C., P. Langhorne, and J. Grimshaw. 1997. Integrating heterogeneous pieces of
evidence in systematic reviews. Annals of Internal Medicine 127(11):989–995.
Murphy, M. K., N. A. Black, D. L. Lamping, C. M. McKee, C. F. Sanderson, J. Askham,
and T. Marteur. 1998. Consensus development methods, and their use in clinical
guideline development. Health Technology Assessment 2(3):1–88.
NIH (National Institutes of Health). 2010. The NIH Consensus Development Program.
Kensington, MD: NIH Consensus Development Program Information Center.
http://consensus.nih.gov/aboutcdp.htm (accessed July 16, 2010).
NPAF (National Patient Advocate Foundation). 2011. National Patient Advocate Founda-
tion launches Comparative Effectiveness Research (CER) Database. http://www.npaf.
org/images/pdf/news/NPAF_CER_010611.pdf (accessed February 1, 2011).
Oxman, A., and G. Guyatt. 1993. The science of reviewing research. Annals of the New
York Academy of Sciences 703:125–133.
Pagliari, C., and J. Grimshaw. 2002. Impact of group structure and process on mul -
tidisciplinary evidence-based guideline development: An observational study.
Journal of Evaluation in Clinical Practice 8(2):145–153.
PIPC (Partnership to Improve Patient Care). 2011. Welcome to the CER Inventory.
http://www.cerinventory.org/ (accessed February 1, 2011).
Richardson, W. S., M. S. Wilson, J. Mishikawa, and R. S. A. Hayward. 1995. The well-
built clinical question: A key to evidence based decisions. ACP Journal Club
123(3):A12–A13.
Rockey, S. J., and F. S. Collins. 2010. Managing financial conflict of interest in biomedi-
cal research. JAMA 303(23):2400–2402.
Roundtree, A. K., M. A. Kallen, M. A. Lopez-Olivo, B. Kimmel, B. Skidmore, Z. Ortiz,
V. Cox, and M. E. Suarez-Almazor. 2008. Poor reporting of search strategy
and conflict of interest in over 250 narrative and systematic reviews of two
biologic agents in arthritis: A systematic review. Journal of Clinical Epidemiology
62(2):128–137.
Sacks, H. S., J. Berrier, D. Reitman, V. A. Ancona-Berk, and T. C. Chalmers. 1987.
Metaanalyses of randomized controlled trials. New England Journal of Medicine
316(8):450–455.
OCR for page 45
80 FINDING WHAT WORKS IN HEALTH CARE
Sawaya, G. F., J. Guirguis-Blake, M. LeFevre, R. Harris, D. Petitti, and for the U.S. Pre-
ventive Services Task Force. 2007. Update on the methods of the U.S. Preventive
Services Task Force: Estimating certainty and magnitude of net benefit. Annals
of Internal Medicine 147(12):871–875.
Schünemann, H. J., A. Fretheim, and A. D. Oxman. 2006. Improving the use of re -
search evidence in guideline development: Grading evidence and recommenda-
tions. Health Research Policy Systems 4:21.
Shrier, I., J. Boivin, R. Platt, R. Steele, J. Brophy, F. Carnevale, M. Eisenberg, A. Furlan,
R. Kakuma, M. Macdonald, L. Pilote, and M. Rossignol. 2008. The interpretation
of systematic reviews with meta-analyses: An objective or subjective process?
BMC Medical Informatics and Decision Making 8(1):19.
Silagy, C. A., P. Middelton, and S. Hopewell. 2002. Publishing protocols of systematic
reviews: Comparing what was done to what was planned. JAMA 287(21):2831–
2834.
Slutsky, J., D. Atkins, S. Chang, and B. Collins Sharp. 2010. AHRQ Series Paper 1:
Comparing medical interventions: AHRQ and the Effective Health-Care Pro -
gram. Journal of Clinical Epidemiology 63(5):481–483.
Srivastava, R., C. Norlin, B. C. James, S. Muret-Wagstaff, P. C. Young, and A. Auerbach.
2005. Community and hospital-based physicians’ attitudes regarding pediatric
hospitalist systems. Pediatrics 115(1):34–38.
Sun, X., M. Briel, S. Walter, and G. Guyatt. 2010. Is a subgroup effect believable? Up -
dating criteria to evaluate the credibility of subgroup analyses. BMJ 340:c117.
Tunis, S., D. Stryer, and C. M. Clancy. 2003. Practical clinical trial: Increasing the
value of clinical research for decision making in clinical and health policy. JAMA
290(12):1624–1632.
Whitlock, E. P., C. T. Orleans, N. Pender, and J. Allan. 2002. Evaluating primary care
behavioral counseling interventions: An evidence-based approach. American
Journal of Preventive Medicine 22(4):267–284.
Whitlock, E. P., S. A. Lopez, S. Chang, M. Helfand, M. Eder, and N. Floyd. 2010.
AHRQ Series Paper 3: Identifying, selecting, and refining topics for comparative
effectiveness systematic reviews: AHRQ and the Effective Health-Care Program.
Journal of Clinical Epidemiology 63(5):491–501.
Woolf, S. H., C. G. DiGuiseppi, D. Atkins, and D. B. Kamerow. 1996. Developing
evidence-based clinical practice guidelines: Lessons learned by the U.S. Preven -
tive Services Task Force. Annual Review of Public Health 17:511–538.