TY - CONF T1 - Sample size of four clusters-per-arm as a rule of thumb for pilot cluster-randomised controlled trials JO - Trials UR - https://eprints.whiterose.ac.uk/id/eprint/159944 PY - 2019/10/22 AU - Lewis J AU - Scharr SJ ED - DO - DOI: 10.1186/s13063-019-3688-6 PB - BioMed Central VL - 20 IS - Suppl_1 Y2 - 2025/07/04 ER -