Whenever a psychological test uses a format other than machine-scored multiple-choice items, some degree of judgment is required to assign points to answers. Fortunately, most tests have well-defined criteria for answers to each question. These guidelines help minimize the impact of subjective judgment in scoring. However, subjectivity of scoring as a source of measurement error can be a serious problem in the evaluation of projective tests or essay questions. With regard to projective tests, Nunn ally points out that that projective tester might undergo an evolutionary change in scoring criteria over time, coming to regard a particular type of response as more and more and more pathological with each encounter