Statistics for the hand surgeon. Part 1: principles and application to hand surgery research.

Hand surgeons have the potential to improve patient care, both with their own research and by using evidenced-based practice. In this first part of a two-part article, we describe key steps for the analysis of clinical data using quantitative methodology. We aim to describe the principles of medical statistics and their relevance and use in hand surgery, with contemporaneous examples. Hand surgeons seek expertise and guidance in the clinical domain to improve their practice and patient care. Part of this process involves the critical analysis and appraisal of the research of others.

Statistics for the hand surgeon. Part 2: avoiding common pitfalls.

In this second of a two-part article, we describe some of the common statistical pitfalls encountered in hand surgery research. These include dichotomania, the 'Table 2 fallacy', p-hacking, regression to the mean, overfitting and unaccounted data clustering. We explain the impact of these pitfalls on hand surgery research and describe techniques to avoid them. The aim of this two-part article was to provide a starting point for hand surgeons to refer to when conducting or analysing research and provide resources and references for interested readers to explore.