Only recently, however, have corporations begun to investigate the relationship between drug test results and employment criteria. Studies have shown statistically significant relationships between drug testing results and various employment outcomes including absenteeism, turnover, disciplinary actions, and work-related injuries. Although these studies have varied in terms of methodology and purpose, their findings can translate into sizable cost savings for businesses. A study of 5,456 Postal Service job applicants, 4,403 of whom were eventually hired, showed similar results for those employees who tested positive for drug use. The disparities between employees who did and did not use drugs increased with time on the job. The study was then expanded to include several additional job performance indicators including the relationship between drug test results and Employee Assistance Program referrals, medical benefits use, and disciplinary offenses. Specific analyses of these outcome measures showed that employees who tested positive at pre- employment were at much higher risk for experiencing later problems than those who tested negative.