Shortening the Work Preference Inventory for use with physician scientists: WPI-10.

The Work Preference Inventory (WPI) is a four-factor, 30-item measure that assesses work motivation. Used to help individuals choose appropriate career paths, its length contributes to response burden, especially when combined with other measures. We aimed to develop a shortened, valid, and reliable version of the WPI. Trainees at the University of Pittsburgh's Institute for Clinical Research Education completed the 30-item WPI between 2007 and 2012. We conducted exploratory and confirmatory factor analyses to reduce the number of items. Of the 402 eligible trainees, 371 (92%) provided data for the exploratory factor analysis (EFA), and 134 of the eligible 144 trainees (93%) provided data for the confirmatory factor analysis (CFA). EFA revealed four factors that were roughly equivalent to those of the original. CFA used the three items with the highest loadings on each factor, with two items removed due to low loadings and R-squareds, resulting in a 10-item scale. Cronbach's alpha for each of the four factors ranged from 0.68 to 0.76. Factors in the WPI-10 were strongly and significantly associated with factors in the original WPI, indicating strong validity of the shortened measure. The WPI-10 shows evidence for similar validity and reliability to the original instrument while reducing respondent burden.