A qualitative exploration of the production of Hospital Episode Statistics in a Guernsey hospital: implications for regional comparisons of UK health data.

Hospital Episode Statistics (HES) are widely used in the UK for audit and research. This often includes comparisons between different geographical regions, but there is some doubt as to the reliability of comparisons made using these data. Previous studies have focused on the quantitative accuracy of the coding, but not the full data chain. This study is a qualitative examination of the production of HES in a small hospital in Guernsey, which is not part of the NHS. Interviews were conducted with key participants in the production of HES to determine how the data were created, and the strengths and weaknesses of this system. We found that face-to-face communication between administrative and clinical staff was felt to contribute to the accuracy of the HES codes, and that a lack of detail in the case-notes was felt to be more problematic than the accuracy of the coders themselves. These findings have implications for the comparison of HES between NHS Trusts, since the processes involved in producing the data will be different in larger hospitals with less contact between coders and clinicians. It is therefore important to bear this in mind when making comparisons between such diverse sources of HES.