The most common sampling method is the convenience sample; therefore, many of the studies that you find for evidence use this sampling method. What are the implications of using a convenience sample for the way you interpret and use the findings?
Convenience sampling is the most commonly used technique due to its ease. The sampling here is based on the availability of the evidence and its proximity. The samples gathered in this manner are not representative of the population and generalizations can not be made based on results of convenience sampling.
As stated, if the researcher is using a convenience sample, the findings are not representatives of entire population and the results are only applicable to the sample group. Such findings are more suitable for pilot-testing. A full scale study will require representative samples and not convenience samples. Thus a convenience sample will limit the interpretation to pilot scale level and not as a generalization.
Consider the case when the jury is selected from a group of retired employees, simply because they are free and more accessible than a well-represented population group. IN such a scenario, the jury may be unduly biased against something (e.g., abortion or same-sex relationships) and the result will reflect this bias. The ruling will not be applicable to all the cases, since a well-mixed jury may feel differently.
So one has to be careful when interpreting the results obtained from a convenience sampling-based study.