As a result, any concept of mismatch based on individual skills offers only a partial view of the match between a w'orker and his or her job. Qualifications reflect several different skills, including both information-processing and job-specific competences, and could complement narrower, though more precise, skills measures. In addition, skills use depends, at least partly, on the effort that workers decide to put into their jobs, making it difficult to define precise skills requirements, qualification requirements are easier to define.