Mastering variation: Variance components and personalised medicine

Stephen Senn*

*Corresponding author for this work

    Research output: Contribution to journalArticleResearchpeer-review

    124 Citations (Scopus)


    Various sources of variation in observed response in clinical trials and clinical practice are considered, and ways in which the corresponding components of variation might be estimated are discussed. Although the issues have been generally well-covered in the statistical literature, they seem to be poorly understood in the medical literature and even the statistical literature occasionally shows some confusion. To increase understanding and communication, some simple graphical approaches to illustrating issues are proposed. It is also suggested that reducing variation in medical practice might make as big a contribution to improving health outcome as personalising its delivery according to the patient. It is concluded that the common belief that there is a strong personal element in response to treatment is not based on sound statistical evidence.

    Original languageEnglish
    Pages (from-to)966-977
    Number of pages12
    JournalStatistics in Medicine
    Issue number7
    Publication statusPublished - 30 Mar 2016


    • Components of variation
    • Cross-over trials
    • N-of-1 trials
    • Personalised medicine
    • Random effects


    Dive into the research topics of 'Mastering variation: Variance components and personalised medicine'. Together they form a unique fingerprint.

    Cite this