In Holland's theory, there are six personality types that correspond to a set of occupations. Holland proposed “that [job] satisfaction is highest and turnover is lowest when personality and occupation are aligned” (Robbins & Judge, 2009, 122). Thus, people in jobs that match their personality are more likely to be satisfied with their jobs than people in incongruous occupations (Robbins and Judge, 2009). With this information, managers could significantly increase their staff's job satisfaction by placing employees in job opportunities that match their personalities. If Holland's theory is correct and employees are honest when reviewing the Job Preference Inventory, then the theory could be an effective tool for reducing the number of jobs.