This report summarizes two nationwide studies conducted by the National Assessment of Educational Progress (NAEP), in 1969-70 and 1972-73, in which information was gathered on the skills and knowledge in science of respondents aged 9, 13, and 17. Included in this report are: a description of the sample used and the science exercises used; statistical results of the studies according to age, region of the country, sex, and region and type of community; and supplementary graphs and tables displaying the data. (MH) Primary type of information provided by report: Results (Overview).