Biology content cognitive structure: From science student to science teacher

The F-Sort of Biology Concepts was used to assess understanding of the relationships among 37 biology concepts by five groups: Preservice secondary science teachers, in-service biology teachers with 1–3 years of teaching experience, in-service biology teachers with 5 or more years of experience, scientists in any biological science field, and college seniors majoring in biology. Data collected from the F-sort were analyzed using latent partition analysis and alpha factor analysis with additional interpretation from multidimensional scaling. The subjects were asked to think aloud as they performed the F-sort and each session was audiotaped for later analysis. These analyses indicated that the biology major and experienced secondary science teachers were separated from the scientists by a dimension based on a deep-versus-surface structure understanding of the concepts. A second axis shows that scientists are separated from other groups by a fluid-versus-fixed cognitive structure dimension. That is, both experienced teachers and scientists were found to have well-constructed and ordered cognitive structures, but scientists were much more likely to see an item having a place in two or more categories, whereas experienced teachers tended to focus on only one aspect of an item, and therefore understanding that it rightfully belonged in only one category. It appears that teachers restructure their science knowledge as they become more experienced. There is an apparent transition from poorly organized to highly organized cognitive structures for biology concepts when comparing preservice, novice, and experienced teachers, respectively. The transition does not seem to be one achieving a deeper understanding of the biology concepts or to a greater degree of integration of the concepts, but rather a transition from a fairly large, loosely organized pool of biology concepts to one which is highly structured but limited to the expectations of the established curriculum. The results have implications for the well-known conjecture that teaching helps one better understand the content being taught.     

Predicting the likelihood of matriculation for college applicants

This paper reports on the collection and analysis of survey data directed toward eliciting those characteristics of the institution, applicant, and applicant's family which affect the matriculation decision. Survey data were collected from freshman students accepted for 1981 and 1982. Discriminant analysis of both a parsimonious and an inclusive set of questions items was conducted, demonstrating that a small subset of the items could predict matriculation with an overall accuracy of 70% correct. Also, there was marked consistency in the effective set of predictor variables over the two year period. Using factor analysis it was shown that all of the predictor variables could be grouped into four composite variables reflecting institutional characteristics, admissions office activities, family attributes, and the cooperative education plan. Finally, we suggest ways in which the results may influence recruiting activities so that limited resources may yield more matriculants.     

The Effects of Score Group Width on the Mantel-Haenszel Procedure

Previous research examining the effects of reducing the number of score groups used in the matching criterion of the Mantel-Haenszel procedure, when screening for DIF, has produced ambiguous results. The goal of this study was to resolve the ambiguity by examining the problem with a simulated data set. The main results from this study call into question the preliminary recommendations of several other researchers that four or more score groups are sufficient and produce stable results. Although considerable stability and very little Type I error was noted with equal ability distribution comparisons, with unequal ability distributions, the Type I error rate was substantially inflated. These results argue against the appropriateness of implementing the procedure by collapsing score groups. The current data suggest that more than modest reductions in the number of score groups cannot be recommended when the ability distributions of the reference and focal groups differ