Skills decay over time without practice or use. During operational tours, fighter pilots may fly fairly uneventful missions (e.g., combat air patrol) with few opportunities to employ their skills (in contrast to peacetime training missions). With fewer opportunities to practice, skill sets will decay. An extended uneventful tour of duty can therefore lead to less capable and less proficient pilots.

This paper reports results of a skill retention study conducted with operational F-16 pilots at the Air Force Research Laboratory (Mesa, AZ). One goal of the study was to identify skills that decayed over time. After participating in a week of Distributed Mission Operations (DMO) training, pilots' performance was assessed using objective mission outcome and process measures. Following a retention interval of three or six months (during which pilots continued normal Air Force duties), pilots' performance was reassessed. The study did not attempt to measure pure skill decay (i.e., no practice during the retention interval), but instead used a more realistic measure-residual skill decay. The operational duties performed by pilots during the retention interval provided some degree of practice that could moderate the decay of some skills.

Execution of the study revealed a host of challenges associated with measuring residual skill decay in an operational training environment, and the results did not reveal convincing levels of residual skill decay. However, we strongly suspect that decay did occur but that a number of factors prevented us from being able to detect it, including (a) small sample size (typical with longitudinal studies); (b) significant training gains for all performance metrics (ceiling effect); (c) highly experienced pilots (moderating decay); and (d) the nature of the practice obtained during the retention interval. We conclude with recommendations for overcoming these challenges and suggest looking beyond the traditional null hypothesis.