Recruitment Modeller is a tool for clinical researchers undertaking studies which require the prospective rectuitment of participants from multiple centres.

It implements the conditional model, as described in A systematic review of models to predict recruitment to multicentre clinical trials by Barnard, Dent and Cook, and because the maths is similar can generate and show the unconditional model too. Of course the unconditional model is rarely useful, except in single centre studies, but may be interesting as a best case example of what can be achieved.

The models used in Recruitment Modeller are deterministic - that is they produce the same answer every time. They are also - obviously - only as good as the parameters they are given. It’s well known that trials tend to over predict their ability to recruit. You’ll only get a good prediction from Recruitment Modeller if you give it good data.

What a modelling tool like does facilitate, however, is rapid sensitivity analysis through the comparison of possible recruitment profiles across a variety of study scenarios, and tracking actual recruitment as it occurs.

It’s free to download, and in most cases free to use.