Journal of Occupational Rehabilitation, Vol. 14, No. 2, June 2004 (2004)
The Interrater Reliability of a Functional Capacity
Evaluation: The Physical Work Performance Evaluation
Marie-Jos´e Durand,1,2,8 Patrick Loisel,2,3 St´ephane Poitras,4
Richard Mercier,5 Susan R. Stock,6 and Jacques Lemaire7

The purpose was to evaluate the interrater reliability of the Dynamic Strength, Position
Tolerance, and Mobility tasks of the Physical Work Performance Evaluation (PWPE), a
Functional Capacity Evaluation often used with workers disabled due to back pain. For
each worker’s evaluation, two raters were preselected among five trained raters. One of the
raters administered the PWPE while the other functioned as a silent rater. A convenience
sample of 40 workers disabled due to back pain and referred to an occupational rehabilitation
center was used. In general, the reliability was “substantial” (0.61 = ? = 0.80)
to “almost perfect” (0.81 = ? = 1.00) for most of the 21 tasks and three sections of the
PWPE evaluated with the exception of three tasks in the Mobility section (ladder climbing
(? = 0.47), repetitive trunk rotation—standing (? = 0.54), and repetitive trunk rotation—
sitting (? = 0.37)) task and the Mobility section itself (? = 0.54). Several reasons could
explain the lower agreement on the observation of the physical signs associated with these
tasks. Since these tasks involve rotation movements or complex neuromuscular integration,
it seemed difficult for the raters to define what are the normal physical signs and when
physical signs of maximal functional capacity are present. The criteria for establishing the
presence of the physical signs in the PWPE should be improved.