Table 2.
ARIMA models, goodness-of-fit, stationary R2, and effect coefficient (ω) for the impact assessments of the NYC and Madrid birth outcomes with (a) a pulse or short-term-change-independent variable and (b) a level or permanent (perm)-change-independent variable
| Sites and outcomes | ARIMA model | Fit statistics | Stationary R2 | Effect coefficient for event variable |
|---|---|---|---|---|
| NYC | ||||
| LBW pulse and perm | (0,1,1) (0,0,0) | Q = 11.8 df = 17 p = 0.812 | 0.26 | ω = 0.005 p = 0.979 |
| Preterm birth pulse | (1,0,0) (1,0,1) | Q = 12.3 df = 15 p = 0.659 | 0.09 | ω = −0.001 p = 0.992 |
| Preterm perm | (0,1,1) (1,0,1 | Q = 14.9 df = 15 p = 0.462 | 0.32 | ω = −0.026 p = 0.914 |
| IMR pulse | (0,1,1) (1,1,1)a | Q = 20.4 df = 15 p = 0.158 | 0.65 | ω = 0.118 p = 0.820 |
| IMR perm | (0,1,1) (1,1,1)a | Q = 20.7 df = 15 p = 0.146 | 0.68 | ω = 0.967 p = 0.003 |
| Madrid | ||||
| LBW pulse | (0,1,1) (1,1,0)b | Q = 16.6 df = 16 p = 0.410 | 0.79 | ω = 1.247 p < 0.001 |
| LBW perm | (0,1,1) (1,1,0)b | Q = 16.6 df = 16 p = 0.410 | 0.79 | ω = 1.247 p < 0.001 |
| Preterm birth pulse | (1,1,0) (1,0,1)b | Q = 15.7 df = 15 p = 0.405 | 0.40 | ω = 1.33 p < 0.01 |
| Preterm birth perm | (1,1,0) (1,0,1)b | Q = 12.8 df = 15 p = 0.614 | 0.51 | ω = 0.198 p = 0.390 |
| IMR pulse | (0,1,1) (0,1,1)c | Q = 8.4 df = 16 p = 0.937 | 0.65 | ω = 0.585 p = 0.587 |
| IMR perm | (0,1,1,) (0,1,1)c | Q = 9.1 df = 16 p = 0.911 | 0.65 | ω = −0.790 p = 0.204 |
aDummy variable 1-year delayed so that the intervention =0 for quarter 1, 1990 to quarter 3, 2002 and =1 for quarter 4, 2002 to quarter 4, 2008
bOutliers controlled
cDummy variable 1-year delayed so that the intervention =0 for quarter 1, 1990 to quarter 1, 2005 and =1 for quarter 2, 2005 to quarter 4, 2009