Skip to main content

Table 3 Interrupted time series model output

From: Humanitarian surgical service utilization by a host country population: comparing surgery patterns between refugees and Tanzanians using an interrupted time-series analysis

  IRR 95% confidence interval p value
Intercept: baseline average number of surgeries among Tanzanians, 2010, Q1 24.8 19.1–32.4  < 0.001
T, slope prior to intervention among Tanzanians (ratio of average number of surgeries per quarter) 1.06 1.04–1.08  < 0.001
Z, ratio of average surgery counts between Refugees and Tanzanians at baseline (2010, Q1) 3.21 2.35–4.38  < 0.001
Z x T, ratio of slopes prior to intervention between Refugees and Tanzanians 0.96 0.94–0.99 0.005
X, ratio of average surgery counts in the
period immediately following intervention (2015, Q1) to the last pre-intervention quarter (2014, Q4) among Tanzanians
0.62 0.46–0.84 0.002
X x T, ratio of postintervention and pre-intervention slopes for Tanzanians 0.96 0.93–0.98 0.001
Z x X interaction, ratio of the post-intervention change in average number of surgeries between Refugees and Tanzanians, in the period
immediately following intervention (i.e. 2015, Q1) compared to the last pre-intervention quarter (2014, Q4)
1.92 1.35–2.74  < 0.001
Z x X x T interaction, ratio of ratios of post-vs. pre-intervention slopes between Refugees and Tanzanians (“difference in difference” on multiplicative scale) 1.04 1.00–1.07 0.028