1. Results summary.

	Dale 1995 (N = 4641)	Murphy 1996 (N = 4684)	Gibney 1999 (N = 1878)
Laboratory investigations ordered	RR 0.22, 95% CI 0.14 to 0.33	RR 0.35, 95% CI 0.29 to 0.42	RR 0.96, 95% CI 0.76 to 1.2
X‐rays ordered	RR 0.47, 95% CI 0.41 to 0.54	RR 0.77, 95% CI 0.72 to 0.83	RR 1.07, 95% CI 0.99 to 1.15
Admissions	RR 0.33, 95% CI 0.19 to 0.58	RR 0.45, 95% CI 0.36 to 0.56	RR 1.11, 95% CI 0.70 to 1.76
Referrals to specialists	RR 0.50, 95% CI 0.39 to 0.63	RR 0.66, 95% CI 0.60 to 0.73	RR 1.21, 95% CI 1.09 to 1.33
Prescriptions	RR 0.95, 95% CI 0.88 to 1.03	RR 1.45, 95% CI 1.35 to 1.56	RR 1.12, 95% CI 1.01 to 1.23

CI: confidence interval; RR: risk ratio