Any evaluation of the relative effectiveness of services or curricular options offered to students identified as gifted, and particularly to minority students who are identified as gifted, is hampered by the relative lack of empirical research on intervention effects. As noted throughout this report, the field of gifted education is characterized by a literature with a very small research base. Rogers (1989) concluded from her review of the major databases that only 32 percent of all citations were reports of research. In 1990, Carter and Swanson identified 1,700 articles focusing on giftedness, winnowed them to prominent, frequently cited articles, and found that only 29 percent were based on data compared with 78 percent of a similarly devised list of articles on learning disabilities. More recent reviews by Ziegler and Raul (2000) of articles published in 1997 and 1998 in the five journals addressing gifted education and by Heller and Schofield (2000), of six journals published between 1992 and 1998 reaffirmed that only a small proportion of publications in gifted education are data based (33 percent in the Ziegler and Raul study and 23 percent in the Heller and Schofield analysis).
Shore et al. (1991) concluded that of 110 recommended practices in gifted education, only 40 percent were supported by empirical evidence in the literature, “most of them marginally, and few of these directly address curriculum, programming or pedagogy” (p. 279). While there has been a body of research that has addressed many of these pedagogical issues related to the gifted population since that time, problems surrounding interpretation of the results prevail. Among those problems is the wide variability in definition of giftedness used in the studies, making comparison and generalization difficult.
A methodological shortcoming of many of the studies is the use of single-sample reporting (lack of control groups or comparison groups) or equal quality control in qualitative studies, which limits interpretation of the findings. For example, Ziegler and Raul (2000) report that only 20 of 90 data-based articles they reviewed included control group information. Furthermore, in many cases the populations studied were derived from groups determined by identification procedures of local school divisions rather than researcher-imposed criteria for giftedness or researcher assessment, leaving exact determination of the groups served as gifted somewhat vague and indeterminate.
The drawing of clear, sound conclusions from the research base is hampered by the intertwined variables of differing program delivery options and curricular offerings and the assessment of broad curricular models with multiple and varied expected outcomes rather than specific instructional strategies. For example, the term “acceleration” may refer to early entrance to kindergarten, grade skipping, or early entrance to college, or it may mean acceleration of the curriculum while maintaining age-expected grade placement (e.g., independently studying algebra while in third grade). While all of