Abstract The word “statistics” is derived from the Latin for “state”, indicating the historical importance of governmental data gathering, which related principally to demographic information and often to their use in military recruitment and tax collecting. Statistics as an academic study is the science of assembling and interpreting numerical data. In clinical medicine, statistical methods are used to: • determine the accuracy of measurements • compare measurement techniques • assess diagnostic tests • determine normal values • monitor patients. Most surgeons use the results of medical research, whether they are prescribing a new drug or advising patients to cease smoking. All surgeons should have some understanding of ways in which studies are designed.They must also know how data are collected, analysed and interpreted. Statistics is a tool that aids the researcher in organizing and summarizing data, in making inferences about the data, and in communicating research findings clearly and meaningfully to others. The widespread availability of computers (see later) means that more calculations are being performed, and more articles being published than ever before. Hence, the chance of inappropriate statistical methods being applied may actually have increased. Surgeons, as consumers of research, should understand the uses and limitations of statistical techniques. This contribution should be read in conjunction with Reeves, page 129.