Creation and validation of medical data

The problems of creating and validating medical data are discussed. These difficulties relate to the structuring of data and its definiton. The necessity for clarity of thought, coherence and logic in data collection is stressed. Difficulty in medical and lay staff training shows that this is a continuing problem. Data validation must be the major province of senior as well as junior doctors. It is an absoulte essential continuing process and without valid data most analyses are not worthwhile because of high error rates and/or too much missing data.