the student took might assert that the information in the student's response is not as sophisticated as what was taught in the course. In that case, the content of the biology course is being used as the standard for rating the quality of the responses. Alternatively, the standard for rating the appropriateness of the information might be the scientific ideas in the content standards.
Student E's response is rated higher than Student S's on the basis of the quality of information. Student S's justification provides some information about what the student does and does not know and provides some evidence for making inferences about the structure of the student's knowledge. For example, the student did not consider the complementary relationship of photosynthesis and respiration in crafting the justification. Perhaps the student does not know about respiration or that the processes are complementary. Alternatively, the two concepts may be stored in memory in a way that did not facilitate bringing both to bear on the exercise. Testing the plausibility of the inferences about the student's knowledge structure would require having a conversation with the student. To learn if the student knows about respiration, one simply has to ask. If the student knows about it and did not apply it in making the prediction, this is evidence that respiration is not understood in the context of the life processes of plants.
Student E's response is well structured and consistent with the prediction. The statements form a connected progression. The prediction is tentative and the justification indicates it is tentative due to the lack of information in the prompt and the student's uncertainty about the quantitative details of the condition under which photosynthesis and respiration occur. The student is explicit about certain assumptions, for instance, the relationship of minerals in the soil and plant growth. The questions the student poses in the justification can be interpreted as evidence that alternative assumptions have been considered.
In contrast, Student S's prediction is stated with unwarranted assurance and justified without consideration of anything more than the availability of sufficient water. Furthermore, the justification does not proceed in a sequential way, proceeding from general principles or empirical evidence to a justification for the prediction.
Student S's response highlights an important point that justifies separating the scoring of information from the scoring of reasoning. A student can compose a well-reasoned justification using incorrect information. For instance, had the student posed the following justification, the reasoning would be adequate even if the conclusion that the soil is dry were not correct. The reasoning would be rated higher had the student communicated that
Plants need energy to live. Plants get energy from sunlight through a process of photosynthesis. Plants need water to photosynthesize. Because the soil is dry, water can't get to the leaves, the plant can't photosynthesize and will die from lack of energy.
Developing scoring rubrics through moderation requires highly informed teachers experienced in the process. Even when teachers are adequately prepared, the moderation process takes time. The content standards call for knowledge with understanding.