Final answer:
The appropriate measure of validity for pre-employment assessment in a manufacturing plant is to establish an empirical relationship between test scores before hiring and eventual job performance, known as predictive validity.
Step-by-step explanation:
The appropriate measure of validity for a manufacturing plant when it comes to hiring employees would be to establish an empirical relationship between test scores taken prior to being hired and eventual performance on the job. This method attempts to confirm that pre-employment tests are good predictors of future job performance. Validity in this context could be seen in terms of predictive validity, where the test scores of potential hires are correlated with their later job performance, thus providing a way to anticipate the suitability and effectiveness of candidates for the job.