The validity of assessment centers (AC) has been a focus of debate in recent years. Some researchers have argued against the construct validity of AC dimensions, as raters’ scores tend to reflect exercise variance instead of dimension variance (e.g., Sackett & Dreher, 1982). In other words, some researchers have argued that instead of measuring dimension factors as intended, ACs actually measure exercises factors. Furthermore, a few studies have examined the criterion-related validity of exercise factors compared to dimension factors within the same AC, as previous studies used a meta-analysis approach (e.g., Hoffman, Kennedy, LoPilatio, Monahan, & Lance, 2015). The goal of this research was to examine the construct and criterion-related validity of an AC used in selecting for a specialized military employment role. Using Confirmatory Factor Analysis, this study examined the construct validity of the AC and the potential need for dimension ratings by comparing five models: (a) a general competency factor, (b) only dimension factors, (c) only exercise factors, and (d) a model including both dimension and exercise factors. Furthermore, each model was assessed on its criterion-related validity, and its incremental validity beyond a test of general mental ability (GMA) and a five-factor model (FFM) personality test. Results supported the need for dimension ratings over exercise ratings, and the need for the AC in selection, beyond the use of GMA and FFM testing. The validity and value of using ACs for specialized military employment selection purposes will be discussed.