Final answer:
Criterion-related validity is the most important factor when choosing a selection test for recruitment, as it measures the effectiveness of the test in predicting a candidate's future job performance.
Step-by-step explanation:
When choosing a selection test for recruitment purposes, the determining factor tends to be criterion-related validity. This type of validity indicates how well one measure predicts an outcome based on the correlation with a criterion (such as job performance). Criterion-related validity directly addresses whether the test can effectively predict a candidate's future performance at work, which is critical in recruitment. Therefore, among the options of face validity, content validity, construct validity, and criterion-related validity, criterion-related validity is of greatest importance for recruitment selection tests.