The Expected Value of Sample Information (EVSI) can be used to prioritise avenues for future research and design studies that support medical decision making and offer value for money spent. EVSI is calculated based on three key elements. Two of these, a probabilistic model-based economic evaluation and updating model uncertainty based on simulated data, have been frequently discussed in the literature. By contrast, the third element, simulating data from the proposed studies, has received little attention. This tutorial contributes to bridging this gap by providing a step-by-step guide to simulating study data for EVSI calculations. We discuss a general purpose algorithm for simulating data and demonstrate its use to simulate three different outcome types. We then discuss how to induce correlations in the generated data, how to adjust for common issues in study implementation such as missingness and censoring and how individual patient data from previous studies can be leveraged to undertake EVSI calculations. For all examples, we provide comprehensive code written in the R language and, where possible, Excel spreadsheets in the supplementary materials. This tutorial facilitates practical EVSI calculations and allows EVSI to be used to prioritise research and design studies.
Bibliographical noteFunding Information:
NJW was supported by the NIHR Biomedical Research Centre at University Hospitals Bristol and Weston NHS Foundation Trust and the University of Bristol. JDGF was funded in part by a grant from Stanford’s Precision Health and Integrated Diagnostics Center (PHIND). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care.
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: AH was funded in part by an Innovative Clinical Trials Multi-year Grant from the Canadian Institutes of Health Research (funding reference number MYG-151207; 2017–2020), as part of the Strategy for Patient-Oriented Research. MS has no funding to declare. DG has no funding to declare. NK reports funding from the Research Council of Norway (276146 and 304034) and Link Medical Research during the conduct of the study and personal fees from Thermo Fisher Scientific outside the submitted work.
© The Author(s) 2021.
- expected value of sample information
- R tutorial
- research design methods
- simulation methods
- value of information