This study lacks generalizability.
Generalizability is an academic term and describes the process of extending research findings and observations from a study on a sample population to a larger and more diverse population. The larger the sample population, the easier will be to generalize the results to the wider population. In this example, Dr Kirch used a sampling technique called convenience sampling, which involves the selection of the most available and proximate subjects. However, there is sampling bias since the sampling population is not representative of the entire population and therefore the study can not speak for the entire population.
