This study focused on developing group test items which measure the science process skills, "Formulating Hypotheses" and "Defining Operationally". Thirty-six multiple choice questions were developed by using behavioral objectives of "Science - A Process Approach" materials. A group of 56 students who had used these materials were given the Individual Competency Measures Test. Then, the investigator-developed group test was administered to the same children. The scores on the Individual Competency Measures Test served as the external criterion measure for selection of the upper and lower 27 percent categories for calculating group test item discrimination indices. Ten items on the Formulating Hypotheses and eleven items on the Defining Operationally processes were found to have a high index of discrimination. Pearson product-moment correlation coefficients were computed for the two sets of scores from the Individual Competency Measures Test and on 21 investigator-made test items with a high index of discrimination. Items from these two tests were found correlated at .001 level of significance. (Author/PS)