Sensitivity and Specificity of the Blankenship FCE System’s Indicators of Submaximal Effort

Perry N. Brubaker, Frank J. Fearon, Stephen M. Smith, Richard J. McKibben, James Alday, Stacie S. Andrews, Everald Clarke, George L. Shaw, Jr

DOI: 10.2519/jospt.2007.2261

STUDY DESIGN: Single-blinded, randomized, posttest only design. OBJECTIVE: To help contribute to the body of evidence in defining the validity of functional capacity evaluations. BACKGROUND: Functional capacity evalua­tions (FCEs) are tests used to help determine an individual's readiness to return to work. Most FCEs incorporate indicators of effort within the evalua­tion. Published evidence validating the use of these indicators is limited. METHODS AND MEASURES: Forty-nine injured and noninjured individuals 18 to 65 years of age participated in this study. The participants were randomly assigned to 1 of 2 groups: 100% effort or 50% effort. Raters were blinded to partici­pant group. The Blankenship Version 6.0 software was used to analyze the data and a Blankenship FCE validity profile was scored. A score of 70% or greater was deemed a valid FCE as adopted by the Blankenship protocol. RESULTS: The sensitivity of the FCE compo­nents tested was demonstrated to be 80% and specificity was 84.2%. The positive likelihood ratio was 5 and the negative likelihood ratio was 0.2. A receiver operating characteristic (ROC) curve demonstrated the 70% cut-off value for scoring the FCE was optimal. CONCLUSION: Four components of the Blan­kenship FCE system demonstrated good sensitivity and specificity for detecting submaximal effort. However, clinicians should note that false positives (maximum effort identified as submaximal effort) may occur and scores of "equivocal" are not scored in the "criteria passed" category. The rater should be aware that this method of scoring could potentially influence a client's overall FCE score.

 

J Orthop Sports Phys Ther. 2007;37(4):161-168. doi:10.2519/jospt.2007.2261

 

KEY WORDS: ergonomics, false positives, functional capacity evaluation, sincerity of effort, work-related injuries

Four components of the Blan­kenship functional capacity evaluation (FCE) system demonstrated good sensitivity and specificity for detecting submaximal effort in this study. However, clinicians should note that false positives (maximum effort identified as submaximal effort) may occur and scores of "equivocal" are not scored in the "criteria passed" category. The rater should be aware that this method of scoring could potentially influence a client's overall FCE score and thus the assessment of the individual's readiness to return to work.

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