The purpose of this project was to construct a valid and reliable noncurriculum specific measure of integrated science process skills intended for use with middle school students. The major efforts in test development were focused on the refinements and modifications of the set of objectives and test items assessed by the existing Middle Grades Integrated Science Process Skills Test (Cronin and Padilla). Skills associated with planning, conducting, and interpreting results from investigations were delineated, and six objectives encompassing these skills were identified. There were 21 items judged to be the best measures of these objectives chosen for inclusion in the test. The POPS test was constructed in order to assess the process skills dealing with identifying experimental questions, identifying variables, formulating hypotheses, designing investigations, graphing data, and interpreting data. The readability of the test was assessed and an average grade level index of 6.8 was obtained. The POPS test is a reliable instrument for diagnostic and/or summative assessment in science classes or research studies. The test may be a useful means for classroom-based research, evaluation of instruction and learning, and curriculum validation in evaluation as well as assessing process skills competence of middle school students. (MVL)