Depending on your population of interest and the type of sampling used, you may use different methods of recruitment. Often, researchers find it most beneficial to implement multiple methods and combine active and passive methods. Passive methods invite potential participants to contact the researcher for further information, while active methods involve approaching and interacting with potential participants (Harvard Catalyst, 2017). Some examples of passive methods include putting up flyers, posting to public message boards, or leaving out paper surveys at public locations. Active recruitment methods might entail making calls to pre-selected individuals, sending personalized email requests, or handing out flyers to select business owners. Keep in mind that select recruitment methods can be utilized in both active and passive forms. This holds true with respect to social media recruiting: As a passive method, you could put an ad on your school’s newspaper’s website. Alternatively, as an active method, you could directly send emails and friend requests to specific individuals who fit your inclusion criteria.
Note that the type of sampling you use may limit how you can recruit. For non-probability sampling, both active and passive recruitment methods can be effective. However, in the case of probability sampling, passive methods of recruitment are often difficult to implement effectively as these methods can have an uncontrollable impact on the representativeness of the final sample (DeCarlo, 2020).
For example, if you are conducting a study on the favorite restaurants of scuba divers who live in Monterey County, posting a flyer outside a local dive shop does not guarantee that all your respondents will actually be divers who live in Monterey. Given that you have no control over who walks by the store, individuals who answer might live outside of Monterey or not be divers, and thereby not be adequate participants for your study. You would have to obtain more information about each individual to ensure they actually fall within your sampling frame before being able to use probability sampling methods.
Here are some challenges you may encounter when recruiting participants and solutions to these potential roadblocks:
