How many is enough? Justifying sample size in descriptive quantitative research.

Background: Descriptive quantitative researchers often use surveys to collect data about a group or phenomenon. Determining the required sample size in descriptive surveys can pose a challenge as there is no simple 'formula' by which to calculate an appropriate sample. However, when a sample is too small the study may fail to answer the research question and too many responses can create resource implications.

Aim: To explore considerations regarding the justification of adequate sample size in descriptive quantitative research.

Discussion: Several considerations may assist quantitative descriptive researchers in examining the appropriateness and justification of sample size. Response rates can guide decision-making around the proportion of the target population who respond. Additionally, consideration of any validated tools, the spread or responses and types of analysis can guide sampling decisions.

Conclusion: The strategies in this article provide a considered approach to justifying sample size in descriptive quantitative research. Factors such as response rates and analytical considerations provide a transparent means of justifying an adequate sample.

Implications for practice: Providing clear justification for the sample size within descriptive quantitative research demonstrates a robust research approach and optimises resource use.