Sample Size and Sampling Considerations in Published Clinical Research Articles.

AIM: : Appropriate calculation of sample size and choosing the correct sampling technique are of paramount importance to produce studies that are capable of drawing clinically relevant conclusions with generalizability of results. The current study was planned with an objective to determine reporting of sample size and sampling considerations in clinical research articles published in the year 2017.
METHODS: One high impact factor journal and one low impact factor journal belonging to the specialities of Medicine, Surgery, Obstetrics and Gynaecology, Paediatrics and Pharmacology were selected and checked for adherence to reporting of sample size and sampling considerations.
RESULTS: A total of 264 articles were examined. These consisted of 55 interventional studies and 209 observational studies. Interventional studies showed higher reporting of sample size calculation/justification for sample size selection (29.1%) compared to observational studies (14.8%). Only 33 out of 155 articles from high impact factor journals and 14 out of 109 articles from low impact factor journals mentioned about sample size calculation or justified the sample size. In addition to this, merely 68 out of 209 observational studies mentioned about sampling considerations such as sampling technique/participant follow up/matching details.
CONCLUSION: The reporting of sample size and sampling considerations was found to be low in both high impact factor and low impact factor journals. Though interventional studies had better reporting compared to other study designs, the reporting was still not adequate and there is an immense scope for improvement. © Journal of the Association of Physicians of India 2011.