Purpose or mortality monitoring | Detection of murder | Primarily, quality improvement; secondarily, detection of murder |
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Description of monitoring system | Total mortality for individual GPs with correction for over-dispersion was monitored for 1993–2000. Normal log-likelihood ratio CUSUM charts used for detection system. Alarm signals were subsequently investigated in two ways, one based on an open quality-improvement model,9 one more forensic and confidential.4 Neither found cause for concern | Five-year aggregated case-mix-adjusted total mortality for practices was monitored for 1996–2000. Cross-sectional Shewhart charts with three standard deviation control limits used for detection system. Alarm signals were openly investigated using the pyramid model of quality improvement. No cause for concern was found |
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Coverage — what percentage of practices/GPs/nurses were monitored? |
11.8% of practices 37.3% of GPs individually monitored No nurse individually monitored Poor data quality in 1990s meant most practices and GPs excluded
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Ability to detect murderers | Practice monitoring | Uncertain |
| eSDR7 = 74.7% (k = 1, h = 3)a | |
| eSDR7 = 41.2% (k=1, h = 5) | |
| GP monitoring | |
| eSDR7 = 96.6% (k = 2, h = 3)a | |
| eSDR7 = 82.4% (k = 2, h = 5) | |
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False alarms (percentage of GPs/practices signalling, where later investigation concludes there is no cause for concern) | 3.3% of GPs (k = 2, h = 3) | 15.8% of practices |
| 2.3% of GPs (k = 2, h = 5) | Reflects quality of data available for case-mix adjustment |
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How long must reliable data be available for these conclusions to hold? | 7 years | 5 years |
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Comments | Conclusions rely on being able to monitor individual GPs' mortality rates which is no longer even theoretically feasible with the shift to practice-based registration in 2004 | Effectiveness of mortality monitoring to detect mass murder is assumed rather than directly examines |