Given the attrition rate of nearly 30 percent for each entering U.S. Naval Academy class an attrition prediction instrument for use in selection could represent considerable monetary savings. In previous research, the Naval Academy Personal History Booklet (PHB) has shown some validity as a predictor of Academy disenrollment. The present research evaluated a new method of coding and scoring the PHB and Strong Vocational Interest Blank (SVIB). PHBs administered in 1961-1963 as part of Academy application were obtained for 256 men who later disenrolled from the Academy and for 245 men who graduated with their classes. Eight attrition prediction scales were constructed and employed in a double cross-validation design. Half of the scales used only items of the PHB, while half included items based on the screening interview. A single rating based on the interview was also evaluated. The PHB scales are not recommended for operational use in predicting Academy disenrollment, as they have already been surpassed in predictive efficiency by the SVIB. However, some substantial validities for some PHB items suggest that further research be done on a multiple choice biographical inventory to supplement the SVIB. (Author/MJM)