Patient selection can refer to how patients are matched with proposed treatments (in the clinic), or how patients are selected to take part in clinical trials.
For clinical trials, detailed inclusion and exclusion criteria are documented before recruitment of patients can begin. The inclusion and exclusion criteria are an important part of a trial protocol. If they are properly defined, inclusion and exclusion criteria will increase the chances of a trial producing reliable results. They also protect participants from harm and help avoid exploitation of vulnerable people (such as those without the ability to provide informed consent).