Q: If we use a convenience sample, how should we mention the sample size calculation in the Methods section?

Convenience sampling is unlikely to meet the rigor expected of a research paper because conclusions drawn on the basis of a convenience sample have every chance of being biased. The most infamous example of this bias was the poll in which respondents were picked from telephone directories to predict the results of a US presidential election: the sample was hopelessly biased in favor of those who owned telephones. This was in 1936, when everybody did not own a telephone (and for the record, the sample size was about 2.4 million).

The calculation of sample size thus becomes irrelevant, because conclusions drawn from convenience sampling can be valid only for that sample, whereas research requires that your findings are valid for the population.

In short, please consider using convenience sampling for a pilot study, and should you find something interesting, plan a more systematic study with proper, probabilistic sampling.

And for reviewers’ perspectives on sample size, you may refer to the following resources:

• How should I reply if a reviewer says my sample size is small?
• How should I reply to a reviewer comment stating that the sample size is small?
• How can I respond to reviewer comments regarding the sample size of my pilot study?

And in case you need help with designing your study, you may learn more about our related service: Experimental Design service