Investigating the assumptions of the self‐controlled case series method |
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| Authors: | Heather J Whitaker Yonas Ghebremichael‐Weldeselassie Ian J Douglas Liam Smeeth C Paddy Farrington |
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| Institution: | 1. School of Mathematics and Statistics, The Open University, Milton Keynes, UK;2. Department of Non‐Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK;3. Warwick Medical School, The University of Warwick, Coventry, UK |
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| Abstract: | We describe some simple techniques for investigating 2 key assumptions of the self‐controlled case series (SCCS) method, namely, that events do not influence subsequent exposures and that events do not influence the length of observation periods. For each assumption, we propose some simple tests based on the standard SCCS model, along with associated graphical displays. The methods also enable the user to investigate the robustness of the results obtained using the standard SCCS model to failure of assumptions. The proposed methods are investigated by simulations and applied to data on measles, mumps and rubella vaccine, and antipsychotics. |
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| Keywords: | assumptions event dependent exposures event dependent observation period self controlled case series |
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