Secret shopper studies: an unorthodox design that measures inequities in healthcare access.

Secret shopper studies are particularly potent study designs that allow for the gathering of objective data for a variety of research hypotheses, including but not limited to, healthcare delivery, equity of healthcare, and potential barriers to care. Of particular interest during the COVID-19 pandemic, secret shopper study designs allow for the gathering of data over the phone. However, there is a dearth of literature available on appropriate methodological practices for these types of studies. To make these study designs more widely accessible, here we outline the case for using the secret shopper methodology and detail best practices for designing and implementing them.