Gut 62:423-429 doi:10.1136/gutjnl-2011-301489
  • Colon
  • Original article

Single measures of performance do not reflect overall institutional quality in colorectal cancer surgery

  1. Omar Faiz1
  1. 1Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, St Mary's Hospital, London, UK
  2. 2Dr Foster Unit, Department of Primary Care and Public Health, Imperial College London, London, UK
  1. Correspondence to Mr O Faiz, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, St Mary's Hospital, Praed Street, London W21NY, UK; o.faiz{at}
  1. Contributors AMA, CV and OF conceived the study. AMA analysed and interpreted the data. AMA composed and drafted the manuscript and all authors critically revised the manuscript. All authors, external and internal, had full access to all of the data (including statistical reports and tables) in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis. OF is the guarantor.

  • Revised 17 January 2012
  • Accepted 19 January 2012
  • Published Online First 16 February 2012


Objective To evaluate overall performance of English colorectal cancer surgical units identified as outliers for a single quality measure—30 day inhospital mortality.

Design 144 542 patients that underwent primary major colorectal cancer resection between 2000/2001 and 2007/2008 in 149 English National Health Service units were included from hospital episodes statistics. Casemix adjusted funnel plots were constructed for 30 day inhospital mortality, length of stay, unplanned readmission within 28 days, reoperation, failure to rescue-surgical (FTR-S) and abdominoperineal excision (APE) rates. Institutional performance was evaluated across all other domains for institutions deemed outliers for 30 day mortality. Outliers were those that lay on or breached 3 SD control limits. ‘Acceptable’ performance was defined if units appeared under the upper 2 SD limit.

Results 5 high mortality outlier (HMO) units and 15 low mortality outlier (LMO) units were identified. Of the five HMO units, two were substandard performance outliers (ie, above 3 SD) on another metric (both on high reoperation rates). A further two HMO institutions exceeded the second but not the third SD limits for substandard performance on other outcome metrics. One of the 15 LMO units exceeded 3 SD for substandard performance (APE rate). One LMO institution exceeded the second but not the third SD control limits for high reoperation rates. Institutional mortality correlated with FTR-S and reoperations (R=0.445, p<0.001 and R=0.191, p<0.020 respectively).

Conclusions Performance appraisal in colorectal surgery is complex and dependent on stakeholder perspective. Benchmarking units solely on a single performance measure is over simplistic and potentially hazardous. A global appraisal of institutional outcome is required to contextualise performance.


  • Funding AMA is in receipt of funding from the National Institute of Health Research for research into patient safety. National Institute of Health Research had no role in the study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the article for publication. The researchers had complete independence from AMA's funders. PA and AB are employed within the Dr Foster Unit at Imperial, which is largely funded by a research grant from Dr Foster Intelligence (an independent health service research organisation). The Dr Foster Unit at Imperial is affiliated with the Imperial Centre for Patient Safety and Service Quality at Imperial College Healthcare NHS Trust, which is funded by the National Institute of Health Research. The Department of Primary Care and Social Medicine is grateful for support from the National Institute for Health Research Biomedical Research Centre Funding Scheme.

  • Competing interests None.

  • Ethics approval The study was approved under section 251 granted by the National Information Governance Board for Health and Social Care (formerly section 60 by the Patient Information Advisory Group). The authors have had approval for using these data for research from St Mary's local ethics committee since 2002. Application under section 251 of the NHS Act 2006 was undertaken to permit access to patient level HES data.

  • Provenance and peer review Not commissioned; externally peer reviewed.