Table 3.

Chronic care provision — observed, reference, and excess variation

GP service	Mean^b	Observed variation			Reference (expectable) variation^a			Excess variation^d
GP service	Mean^b	10th percentile	90th percentile	Adjusted IDR^c	10th percentile	90th percentile	Adjusted IDR^c	Excess variation^d
Annual chronic care consultations	16.65	0.18	1.74	9.95	0.92	1.07	1.17	8.54
Chronic care procedures^e	33.76	0.03	2.21	8.41	0.64	1.32	1.17	7.21
Outreach home visits	2.55	0.21	1.75	79.55	0.91	1.07	2.07	38.48
Talk therapy	6.48	0.01	2.10	193.73	0.79	1.19	1.52	127.70
General contacts	752.01	0.80	1.23	1.53	0.96	1.03	1.07	1.42

↵a Based on randomly sampled patients from other practices (matched by sex, age, and a propensity score based on the remaining covariates).
↵b Observed service outcomes per 100 patient-years (unadjusted).
↵c Adjusted for age, sex, ethnicity, cohabitation status, household income, working status, educational attainment, and 39 individual mental and physical long-term conditions.
↵d Excess variation (variation related to practice chronic care profile), that is, adjusted IDR/reference IDR.
↵e Blood glucose measurements, electrocardiograms, lung function tests, and home blood pressure measurements. IDR = interdecile ratio, that is, 90th percentile/10th percentile of the observed/expected ratio.