Table 4 How and where SPC was applied: units of analysis*.
| Unit of analysis | Number of articles | References |
|---|---|---|
| Single patients (including patients using control charts themselves) | 9 | 16, 22, 32, 35, 38, 40, 50, 60, 70 |
| Single clinicians | 4 | 37, 52, 62, 66 |
| Outpatient clinic | 3 | 29, 49, 59 |
| An ambulatory nursing centre clinic | 1 | 23 |
| Primary care/family medicine centre | 2 | 34, 63 |
| Population(s) of patients in nursing home(s) | 2 | 16, 51 |
| Staff at mental health residential facility living areas | 1 | 20 |
| Hospital wards | 5 | 26, 33, 56, 61, 65 |
| Department process level | 15 | 17, 19, 21, 25, 27, 30, 39, 42, 45, 53, 54, 57, 64, 68, 71 |
| Hospital department and community‐based orthopaedic surgeons | 1 | 28 |
| Microsystem(s) | 6 | 15, 37, 43, 47, 50, 67 |
| Process that involves more than one department | 6 | 36, 41, 46, 48, 55, 58 |
| Entire hospital | 6 | 18, 21, 24, 31, 44, 69 |
*The units of analysis—the levels at which SPC was applied—are ordered according to the degree of aggregation (from individual patients to entire organisations). Some articles reported data from more than one unit of analysis. A microsystem is defined as “a small group of people who work together on a regular basis to provide care to discrete subpopulations of patients”.72 The distinction between microsystems and other categories is not absolute but a matter of judgment.