The Jenkins Activity Survey (JAS) was developed by C. David Jenkins, Stephen Zyzanski, and Ray Rosenman to measure Type A behavior, which consists of excessive achievement striving, competitiveness, time urgency, and hostility. Type A behavior had previously been implicated as a risk factor for coronary heart disease (CHD) when measured using a structured interview. Beginning with an initial pool of 50 questionnaire items, statistical analyses identified a subset of 21 items that best predicted Type A interview assessments. These include questions about being hard driving and competitive, setting quotas and deadlines for oneself, becoming impatient when others talk slowly, being quick and punctual, and having a high activity level. As a self-administered questionnaire, the JAS has practical advantages over the structured interview. Administration and scoring are more easily standardized and trained interviewers are not needed.