Characteristics of practices in the top 10% (gain most from case-mix adjustment), mid 10%, and bottom 10% when all practices are arranged by magnitude of change in practice-level mean scores after case-mix adjustment
| Description of patient and practice characteristics | Top 10% of practices* | Mid 10% of practices | Bottom 10% of practices |
| Male (%)† | 46 | 42 | 42 |
| Aged <35 (%) | 30 | 15 | 9 |
| White (%) | 45 | 93 | 97 |
| Average percentage fair or poor self-reported health | 30 | 25 | 20 |
| Average percentage IMD quintile 4 or 5 (deprived) | 82 | 43 | 11 |
| Average practice size (registered population) | 3426 | 5072 | 5434 |
| Impact of case-mix adjustment on practice-level means for two questions used in pay-for-performance scheme | |||
| Ability to get urgent appointment‡ | 3.3 | 0.2 | −1.4 |
| Ability to book ahead‡ | 4.3 | 0.2 | −2.1 |
↵* When all practices arranged in deciles by order of magnitude of change in practice-level mean score after case-mix adjustment for Q7 and Q10, with top 10% showing greater benefit from adjustment.
↵† Average for practices in named decile block (top, mid, or bottom 10%).
↵‡ Adjusted minus unadjusted practice-level mean.