Poor effort on cognitive testing in voluntary research predicts failure in US Army Ranger School: Implications for clinical trial design

Abstract

Introduction Failure to provide effortful performance on cognitive testing is not uncommon for participants in clinical trials and can significantly impact sensitivity to treatment effect. Whether poor effort on cognitive testing might relate to other behaviors of interest is unknown. In the current investigation, we examined whether effort on baseline cognitive testing in a randomized controlled trial to enhance resiliency in US Army Officers predicted subsequent success in Ranger school. Methods Baseline data on six cognitive tests were obtained from 237 US Army Officers entering a military training program prior to attempting Ranger School. Participation was voluntary and the Army was not informed of test scores. “Poor effort” was defined by chance-level accuracy or extreme outlier scores. Logistic regression examined likelihood of Ranger success according to the number of tests with poor effort. Results Overall, 170 (72%) participants provided good effort on all tests. For these participants, 47% were successful in Ranger, versus 32% with poor effort on one test and 14% with poor effort on two tests. Logistic regression analysis found poor effort on baseline testing predicted reduced likelihood of Ranger success, β =−.486, p = .005. Discussion A substantial number of participants exhibited poor effort on testing, and poor effort was predictive of failure in Ranger school. Findings highlight the importance of assessing effort in clinical trials involving cognitive outcomes and suggest application of cognitive effort testing in trials where other motivated behavior is targeted. Registration Clinical Trials.gov NCT02908932.