- Poster presentation
- Open Access
Simple tools for projecting patient recruitment
- Paul Silcocks1
© Silcocks; licensee BioMed Central Ltd. 2013
- Published: 29 November 2013
- Public Health
- Clinical Trial
- Survival Analysis
- Simple Calculation
- Trial Design
Poor recruitment to clinical trials is a well-recognised and serious problem. Various predictors of poor recruitment have been identified and of course should be accounted for in trial design. Trial planning however will need a realistic projection of sample recruitment that also allows for random variation – yet available information may be minimal early in the development of a proposal. Such projections are also required when estimating power for survival analyses (the yield of events depends both on numbers and timing of patient accrual) – for example if using the Stata add-on artsurv.
I show here how minimal information, simple formulae and some reasonable assumptions can be combined to estimate both a sensible projection of expected numbers and a plausible range of variation; in turn this variation indicates the extent to which achieving the target sample size may be delayed. Simple calculations also indicate potential gains from restricting eligibility to better-performing sites and the relative lack of benefit from opening better-performing sites first.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.