TABLE 4.

Comparison of Participating and Control Practices Change in Mean ED Asthma Visit Rate per 100 Child-Years (Additional Difference-in-Differences Analyses) for (1) Comparison of Baseline (2014) to 2016 (Includes the Last 3 Months of the Learning Collaborative) and (2) Including Partial With Full Participants Compared to Control Practices

Additional Analyses	Asthma-Related ED Visits per 100 Child-Years	P	95% Confidence Interval
			Lower	Upper
2014–2016
Control 2014	17.93	—	13.83	22.04
Participating 2014	14.11	—	11.57	16.65
Control 2016	21.46	—	15.94	26.98
Participating 2016	13.33	—	10.96	15.70
Difference in differences	−4.31	.17	−10.49	1.88
Including partial participants
(2014–2017)
Control 2014	16.43	—	11.01	21.86
Participating and partial 2014	15.90	—	12.07	19.72
Control 2017	18.15	—	11.79	24.52
Participating and partial 2017	10.34	—	7.84	12.84
Difference in differences	−7.27	.003	−12.97	−1.58

Marginal rates are adjusted for patient (age, sex, and insurance) and practice (specialty, organizational structure, size, geographic region, and FQHC or RHC status). Because all participants are included in the marginal effect calculation, the control estimates for the same year across models are not the same (eg, control 2014 estimates across models). Analyses are also adjusted for patients clustering within practices; SEs are estimated by using the δ method. —, not applicable.