A longitudinal study was conducted to evaluate the U.S. Employment Service's Specific Aptitude Test Battery (SATB) for plumber/pipe fitter from three aspects: technical adequacy of the research; fairness to minorities; and usefulness in the selection of individuals for training as plumber/pipe fitter apprentices. The validation sample consisted of 253 apprentices (including sixty-nine minority group members) in their first year of apprenticeship during 1974-1976 in eight states and the District of Columbia. The tests for this sample were taken from the General Aptitude Test Battery, while on-the-job competency was gauged by supervisors' ratings, and ability to perform five categories of related course work was measured by instructors' ratings. A cross-validation sample was also used, based on data collected in 1953-1954 from 322 apprentices in Texas (the minority group composition of which was unknown). Criterion for this group consisted of category ratings for a combination of job performance and school achievement. SATB was found (1) to be useful in the selection of apprentices; (2) to be fair to minorities; and (3) to meet all criteria for validity using the more recent sample and for cross-validity based on the prior test sample. (The appendixes include the following: statistics for black and nonminority subgroups of the validation sample; descriptive rating scales for employers and instructors; and a job description and the first-year apprenticeship curriculum for plumbers/pipe fitters.) (ELG)