The present study investigated the impact of an antecedent intervention in the form of a daily posted schedule on the interobserver agreement (IOA) assessment of educational goals implemented within a classroom at a private school serving individuals with disabilities. During baseline, the percentage of academic goals with interobserver agreement was low and stable (M = 5%). Teacher performance improved during the intervention (M = 92%). A reversal replicated this effect and performance maintained during 6-week, 6-month, and 1-year follow-up probes. Results suggest a daily posted schedule can effectively increase interobserver agreement assessment by direct-care teaching staff. (Contains 1 figure.)