The WPI provides a valid and dependable measure of personality traits that directly influence a person’s work performance and task effectiveness. The WPI measures 17 personality traits that research has shown are related to work performance. These traits indicate how individuals work with others, approach their tasks, solve problems, manage change, and deal with stress. Outlining the person’s job-related strengths and identifying areas of weaknesses, the WPI is useful for training and development or personnel selection.