The accuracy of decision rules for progress monitoring data is influenced by multiple factors. This study examined the accuracy of decision rule recommendations with over 4,500 second-and third-grade students receiving a tier II reading intervention program. The sensitivity and specificity of three decision rule recommendations for predicting year-end spring benchmark targets was evaluated over different data collection durations under good and poor dataset conditions. Across grade level and dataset quality, the sensitivity of decisions made using trend lines and the median of recent data points tended to improve to acceptable levels after 18 weeks. Specificity tended to decrease around that same time but was less pronounced with the median decision rule method. Limitations and directions for future research are discussed.