Table 1.

Detection of hospital utilization by different methods.

	Self-report alone	EHR review alone	Self-report + EHR review	HIE alone	HIE+HER combined
Any Hospital Utilization (Inpatient or ED)
Number of Events	261	954	1053	1666	1716
Unique Participants	105	159	168	181	183
% of events accurately identified	15.2%	55.6%	61.4%	97.1%	100%
Inpatient Hospitalizations
Number of Events	145	234	284	421	429
Unique Participants	83	114	129	143	145
% of events accurately identified	33.8%	54.6%	66.2%	98.1%	100%
ED visits
Number of Events	116	720	769	1245	1287
Unique Participants	58	126	133	157	158
% of events accurately identified	9.0%	55.9%	59.8%	96.7%	100%

Note: EHR= Electronic health record, HIE= Health information exchange, ED= Emergency Department. Rates are computed using HIE+EHR combination as the best objective standard. EHR review at the index hospital system covered a system of 9 non-pediatric hospital facilities. HIE covered 47 hospital facilities statewide, plus facilities in Washington DC and adjacent states. Numbers and rates cover a 12-month period post study entry.