Table 4

 How and where SPC was applied: units of analysis*

Unit of analysisNumber of articlesReferences
*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.
Single patients (including patients using control charts themselves)916, 22, 32, 35, 38, 40, 50, 60, 70
Single clinicians437, 52, 62, 66
Outpatient clinic329, 49, 59
An ambulatory nursing centre clinic123
Primary care/family medicine centre234, 63
Population(s) of patients in nursing home(s)216, 51
Staff at mental health residential facility living areas120
Hospital wards526, 33, 56, 61, 65
Department process level1517, 19, 21, 25, 27, 30, 39, 42, 45, 53, 54, 57, 64, 68, 71
Hospital department and community-based orthopaedic surgeons128
Microsystem(s)615, 37, 43, 47, 50, 67
Process that involves more than one department636, 41, 46, 48, 55, 58
Entire hospital618, 21, 24, 31, 44, 69