@inproceedings{inproceedings, title = {{Sample size of four clusters-per-arm as a rule of thumb for pilot cluster-randomised controlled trials}}, publisher = {{BioMed Central}}, url = {{https://eprints.whiterose.ac.uk/id/eprint/159944 }}, year = {{2019}}, month = {{10}}, author = {{Lewis J and Scharr SJ}}, doi = {{10.1186/s13063-019-3688-6}}, volume = {{20}}, journal = {{Trials}}, issue = {{Suppl_1}}, note = {{Accessed on 2025/06/28}}}