Examined three methods which can be used to pool single-item-per-subject data collected in intensive time-series studies, determining if method of pooling has an effect on subsequent data analysis. Methods examined were based on simple averaging, difficulty weightings of averages, and the application of the Rasch logistic model. (JM)

Reports research concerning the definition of variables by pupils ages 12 to 14 during investigative work. Findings suggest that an increase in the complexity of an investigation lowers the ability to identify relevant variables and substantive concepts intrude on the ability to define the appropriate dependent variable and to control variables.…