No study design ever is complete without participants. They’re the most essential element of the entire research process. However, study recruitment is often the least predictable part of any study. You can’t force people to participate. Instead, you hope to compensate, incentivize, market, and strategize your way to more reliable, meaningful recruitment.

One way to improve recruitment is to increase the value of any study compensation (often a dollar amount given to participants who successfully complete a study). But you can’t increase that value without exhausting any available recruitment budget. Your finite resources have to be managed and used strategically. How you use any available budget in this study will affect future studies even if you don’t consider it.

The bad news is that this Handbook won’t solve your recruitment problems. Each place you research will need a customized, tailored approach to attract the Most Informative Participant.

The good news is that this Handbook will give you the necessary knowledge to (1) recognize what type of recruitment issues you have, (2) understand how to fight for and use a recruitment budget, and most importantly, (3) start developing strategies to create a sustainable and reliable recruitment engine.

Recruitment engines are covered in Topic 4 of this handbook. The engine isn’t literal but a conceptual model to help you understand how your recruitment efforts all work together and become something reliable and efficient.

Developing and sustaining a recruitment engine requires thoughtful effort. But you can’t ever hope to use one unless you address an important problem: Why isn’t your study recruitment working today?