This paper presents an updated evaluation of the effectiveness of rear seat restraint systems in preventing fatalities. The double pair comparison method, as used by , was applied to Fatal Accident Reporting System (FARS) data for 1985 through 1996. Estimates were derived for outboard occupants wearing rear seat lap belts and lap and shoulder belts. The efficacy of lap belts in preventing fatalities was determined for all fatal and frontal fatal crashes. Effectiveness estimates are presented for the following rear seat outboard occupant age groups: 5–12, 13–17, and 18–64. The adequacy and validity of double pair comparison procedures are also addressed.