Table 3.

Estimated effect of introduction of NHS Direct on changes in use of general practitioner cooperatives

Service	Estimated trend in use per month (%)		Change in trend (95% CI)	Test statistic
	Before introduction	After introduction
NHS Direct areas:
Calls managed by telephone advice	2.7	−0.1	−2.7 (−4.3 to −1.1)	t56=−3.38, P<0.01
Calls resulting in direct contact with doctor	1.8	−1.3	−3.0 (−4.7 to −1.2)	t56=−3.37, P<0.01
All calls	2.0	−0.8	−2.9 (−4.2 to −1.5)	t191=−4.25, P<0.01*
Control cooperatives	0.8	0.9	0.1 (−0.9 to 1.1)	t191=0.17, P>0.5*

^*Test statistic for difference in change in trend between NHS Direct areas and control cooperatives: F_1,7=26.3, P<0.01.