Journal of Counseling Psychology 1978, Vol. 22, No. 3, 204-209 Same-Sex and Cross-Sex Reliability and Concurrent Validity of the Strong-Campbell Interest Inventory Mary C. Whitton Department of Guidance and Personnel Services North Carolina State University at Raleigh Reliability and concurrent validity data for the Strong-Campbell Interest Inventory (SCII) were developed for a sample of 180 students scored on ap- propriate sex norms and scales. These data were compared with data for the Strong Vocational Interest Blank (SV.IB), data reported in the SCII Manual, and data for the same sample scored on the opposite sex's norms and scales and scored disregarding sex. Two-week test-retest reliability correlations were approximately .90. Agreement between high scores and self-reported curriculum and occupational preferences ranged from 32% to 60%. The SCII has same-sex reliability and concurrent validity near those of the SVIB. Cross-sex scores are not significantly less reliable and valid. Scoring on all Occupational scales produces significantly higher concurrent validity. The appearance of a new edition of a test leaves many users skeptical until its tech- nical and practical value is demonstrated by more data than are given in the test manual. The new merged form of the Strong Vocational Interest Blank (SVIB), the Strong-Campbell Interest Inventory (SCII), incorporates changes which make it more than just a new edition of the SVIB. The most significant change is that one form of the SCII is provided for both men and women. A result of combining the men's and women's forms is that in addition to appro- priate sex (same-sex) scores, a subject's scores on the scales of the opposite sex (cross-sex) are available. Strong (1943, 1966), Perry and Cannon (1967, 1968), Campbell (1971), and the Association for Measurement and Evalua- tion in Guidance Commission on Sex Bias in Measurement (1973) recommended against using one or all of the cross-sex scales. Seder (1940), McCornack (1956), Laime and Zytowski (1963), and Stanfiel (1970) have said that the men's form or some of the men's scales were useful for some women. Campbell (1974) recommended that a person The author wishes to thank David P. Campbell for his generous help without which this project would not have been possible. Requests for reprints should be sent to Mary C. Whitton (now at The Street Academy, Charlotte- Mecklenburg Public Schools), P. O. Box 12521, Charlotte, North Carolina 28205. be given his or her scores on all scales of the SCII. Presented with conflicting results and opinions, the SVIB user had little data on which to base a decision about the use of cross-sex scores. The SCII user has no hard data. The present study was undertaken to provide data on the SCII and on cross-sex scoring by developing and comparing data on the reliability and concurrent validity of the SCII scales for a sample scored on same-sex scales, cross-sex scales, and all scales without respect to sex. METHOD Subjects The 180 subjects for the study were 106 female and 74 male students from several high schools and colleges near Raleigh, North Carolina. The high school students were all seniors and the college students were predominantly freshmen and sopho- mores. The subjects ranged in age from 17 to 55 years with a mean age of 18.9 years. The SCII manual recommends use of the instrument with persons over 17 years old (Campbell, 1974). Procedure The instrument used was the Strong Vocational Interest Blank Merged Form T325, known as the Strong-Campbell Interest Inventory (Strong & Campbell, 1974). Each subject completed a per- sonal data sheet indicating sex, proposed or actual college major, choice of job after graduation, and permanent address. 204