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Table 2 Rate of concussion-related medical encounters per 10,000 member months from 2008 to 2016, autoregressive integrated moving average (ARIMA) intervention models with three breakpoints

From: Analyzing the impact of a state concussion law using an autoregressive integrated moving average intervention analysis

Concussion Law Intervention Breakpoints Change ARIMA model and noise*
Percentage of Change 95% CI P Specification Q24a P
Period 1 Feb,2010 3.6 −4.0 to 11.8 0.3628 (0,1,1)(2,1,0)12 20.13 0.58
Period 2 July,2011 7.3 1.1 to 13.7 0.0186 (0,1,1)(2,1,0)12 21.70 0.48
Period 3 July,2013 2.0 − 4.4 to 8.8 0.5449 (0,1,1)(2,1,0)12 22.70 0.42
  1. *The Ljung-Box Portmanteau (or Q-) test was used to test the randomness of residuals of the estimated models