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.