A class of first graders and a class of second graders in four Salt Lake City schools comprised the experimental sample in a study whose objectives were (1) to develop a test for assessing learning with "Our Working World" materials, published by Science Research Associate (SRA), and (2) to determine if students using the materials made greater learning gains than students not using them. Four classes at each grade level were randomly selected from two schools and served as controls in the investigation. Approximately 400 children took part in the study. Both the experimentals and the controls were given the SRA Test of General Ability. The Primary Economic Test--First Grade (PET-1) of 64 items (devised for this project) was administered to the children after the materials had been used for 3 months. Analysis of covariance was used to adjust group means for differences of scholastic aptitude. It was concluded that (1) the assessment instrument (PET-1) was valuable in testing student progress and (2) the experimental first graders scored significantly higher on the test than did the control students. Attachment A of this document is the PET-1, attachment B contains instructions for administering the test, and attachment C is a chart of selected percentiles and the ranges for the experimental and control groups. (DO)