Estimating hypothetical estimands with causal inference and missing data estimators in a diabetes trial

We (Camila Olarte Parra (LSHTM), Rhian Daniel (Cardiff), myself, and David Wright (AstraZeneca)) recently put on arXiv a new paper which explores the use of estimators from both the causal inference and missing data literatures for estimating a so-called hypothetical estimand in a previously conducted clinical trial in diabetes.

Read more

Multiple imputation and its application – 2nd edition published

I am delighted to write this blog post announcing the publication of the second edition of the book ‘Multiple Imputation and its Application’, published by Wiley, and which I am a co-author along with colleagues James Carpenter, Tim Morris, Angela Wood, Matteo Quartagno, and Mike Kenward.

Key additions in the second edition are:

  • in depth discussion of congeniality and compatibility, and the practical implications of the theory for these for data analysts
  • an updated chapter on performing imputation with derived variables, such as interactions, non-linear effects, sum scores, splines
  • expanded chapter on MI with survival data, including imputing missing covariates in Cox models and MI for case-cohort and nested case-control studies
  • new chapters on multiple imputation for / in the context of:
    • prognostic models
    • measurement error and misclassification
    • causal inference
    • using MI in practice
  • practical and theoretical exercises in each chapter

We hope it will be useful for those handling missing data by multiple imputation in their analyses, particularly in regards to thinking about how to use it in a way which accommodates the various complexities that are often present in statistical analyses.

The book should now be available “in all good bookshops”, as they say. You can find it at Amazon (please note I may receive a commission if you subsequently purchase from Amazon after clicking this link).

G-formula for causal inference via multiple imputation

G-formula (sometimes known as G-computation) is an approach for estimating the causal effects of treatments or exposures which can vary over time and which are subject to time-varying confounding. It is one of the so called G-methods developed by Jamie Robins and co-workers. For a nice overview of these, I recommend this open access paper by Naimi et al 2017, and for more details, the What If book by HernĂ¡n and Robins. In this post, I’ll describe some recent work with Camila Olarte Parra and Rhian Daniel in which we have explored the use of multiple imputation methods and software as a route to implementing G-formula estimators.

Read more