INTRODUCTION: The Dynamic Appraisal of Situational Aggression (DASA) is used to appraise risk of imminent aggression in inpatient mental health settings. AIM: We investigated whether individual patients' mean DASA scores over multiple consecutive time periods (a rolling DASA mean) improved predictive validity, beyond the ultimate DASA rating, and whether DASA ratings were associated with nursing intervention. METHOD: Archival data were analysed using cox regression analyses. We investigated the predictive validity of rolling DASA mean models and calculated how many daily DASA ratings generated a mean score with the best model fit. Chi-Squares with Odds Ratios were used to examine the effect of various aggression prevention intervention(s) on aggression means. RESULTS: Daily DASA ratings had strong predictive validity. Incorporating the ultimate score with the rolling 10-day DASA mean slightly improved prediction. Limit setting was associated with an increased likelihood of aggression for low-risk patients whereas reassurance was associated with increased aggressiveness for those at increased risk of aggression. DISCUSSION: Daily DASA ratings have strong predictive validity. Considering a 10-day rolling DASA mean in addition to the current day DASA rating may improve prediction. IMPLICATIONS FOR PRACTICE: DASA ratings can forecast imminent aggression. Additionally, there may be value in considering ratings from the previous 10 days.