Examined whether population type (voluntary outpatient, voluntary inpatient, coerced outpatient) and question type (alcohol, nonalcohol, demographic) differentially affected the validity of alcoholics' self-reports. Three distinctly different populations of alcohoics--14 voluntary outpatients, mean age, 38.4 yrs, 13 voluntary inpatients, mean age, 44.5 yrs; and 12 coerced outpatients, mean age, 34.2 yrs--independently completed life history questionnaires. The veridicality of Ss' answers was assessed using official records and documents. Generally, Ss gave highly valid self-reports, a result that parallels the findings of earlier studies. Question type differentially affected the validity of Ss' interview answers, as significantly fewer invalid answers were given to demographic questions than to alcohol and nonalcohol questions. Population type, however, did not significantly affect the validity of self-reported life history information. Invalid interview answers were more often overreported than underreported when compared with official records. (11 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1978 American Psychological Association.