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Table 1 Results from the Bayesian changepoint analysis

From: Timing and effect of a safe routes to school program on child pedestrian injury risk during school travel hours: Bayesian changepoint and difference-in-differences analysis

Variable

Posterior mean

95% CrI

SRTS Intervention

Changepoint (δ), number of quarters from January 2001

30.5

(30.02, 30.98)

β0 (Pre-changepoint intercept)

1.25

(0.90, 1.58)

β1 (Pre-changepoint slope)

0.03

(0.02, 0.05)

β2 (Pre- and post intercept difference)

−1.68

(−2.59, −0.84)

β3 (Pre- and post slope difference)

0.04

(−0.1, 0.17)

β0 + β2 (Post-changepoint intercept)

−0.43

(−1.45, 0.52)

β1 + β3 (Post-changepoint slope)

0.07

(−0.06, 0.21)

Non-SRTS Intervention

Changepoint (δ), number of quarters from January 2001

10.49

(10.02, 10.97)

β0 (Pre-changepoint intercept)

4.79

(4.74, 4.85)

β2 (Pre- and post intercept difference)

−0.29

(−0.36, −0.27)

β0 + β2 (Post-changepoint intercept)

4.50

(4.46, 4.53)

  1. Posterior means and 95% Credible Intervals (CrI) on log scale. Safe Routes to School (SRTS) intervention census tracts and non-SRTS intervention census tracts, New York City, 2001–2010.