Unproctored Internet Testing (UIT) is becoming more popular in personnel recruitment and selection. A drawback of UIT is that cheating is easy and, therefore, a proctored test is often administered after an UIT procedure. To detect inconsistent test scores from UIT, a cumulative sum procedure (CUSUM) is proposed. This procedure is applied to empirical data from an adaptive computer-based test in a real personnel selection context. The usefulness of the CUSUM is illustrated, and the unique contribution of the CUSUM to existing procedures is discussed.