Variation in results among practices.
| Strategy A | Strategy B | |
|---|---|---|
| Mean number of patients per practice | 8 | 68 |
| Median number of patients per practice | 5 | 57 |
| Interquartile range | 2–10 | 30–92 |
| Maximum | 67 | 344 |
| Number of practices (out of 480) with no patients identified | 40 | 1 |