Table 1.

Possible explanations for special cause practices.

Practice Code	Primary explanation
1	Nursing home effect
2	Nursing home effect
3	Nursing home effect
4	Nursing home effect
5	Nursing home effect
6	Nursing home effect
7	Very high levels of deprivation and excess morbidity not adequately captured by the case-mix adjustment method
8	High levels of deprivation and excess morbidity not adequately captured by the case-mix adjustment method
9	High levels of deprivation and excess morbidity not adequately captured by the case-mix adjustment method. Practice population becoming younger
10	Practice situated in a violent, deprived area and excess morbidity is not captured by case-mix adjustment method
11	Practice situated in a violent area. Deprivation and excess morbidity not captured by case-mix adjustment method
12	Low levels of deprivation not adequately captured by the case-mix adjustment method. Practice population becoming older
13	Low levels of deprivation not adequately captured by the case-mix adjustment method
14	Very low levels of deprivation and comorbidity not adequately captured by the case-mix adjustment method

An extended version of this table is available as Supplementary information.