A great variety of usability evaluation methods exist but they do not provide the same kind of results and do not address the same stage of the Health Information Technology (HIT) lifecycle. This paper takes stock of the application of expert evaluation, usability testing, clinical simulation, clinical trials and post-implementation surveillance to provide an overview of their main similarities and differences. Results from this comparison will help in choosing methods that are best able to evaluate a HIT and improve its usability and ultimately its safety of use.