Item analyses of the concept assessment kit-conservation for educable mentally retarded children

A series of item analyses of the CAK-C was conducted for a sample of 155 educable mentally retarded children. The probability of a correct response was found to differ from task to task, and there was evidence that the order of difficulty of the tasks for this sample resembled that for nonretarded children. The probabilities of the two incorrect responses were generally not equal, and the choice of one or the other incorrect response showed some relation to CA, MA, and IQ, particularly the last two variables.     

Interpreting the differences: A reply to Kaufman

Kaufman's critique of our article was based on a misunderstanding of our purpose and procedures. This reply clarifies those points and suggests further areas of concern regarding the McCarthy Screening Test.     

High school biology: What makes it a challenge for teachers?

This study contributes to our understanding of the complex issues inherent in dealing with the heterogeneity of current high school science classrooms, by reporting on in-depth interviews with 38 experienced biology teachers. Analyses of teachers' responses revealed complex and occasionally counter-intuitive relationships among: (a) their perceptions of what was distinctive about their school, its biology program, or their students; (b) their allocation of class time; (c) their efforts to individualize instruction and meet the needs of a heterogeneous student population; (d) their student outcome goals; and (e) the methods they used to evaluate student progress. Thus, for example, of the 9 teachers who cited the diversity of their students. 4 also commented on their poor motivation, but another 4 also commented on their high motivation. In addition, teachers reported using a similar range of instructional formats but for different reasons, depending on the characteristics of their students (e.g., cooperative learning groups used to compensate for poor attention spans, to challenge bright students, and to foster social tolerance). Discussion of these findings addresses several points of relevance for science education, teacher preparation, and curriculum reform. © 1996 John Wiley & Sons, Inc.