Standardising measures in pediatric rheumatology: the experience of the international consensus dataset for juvenile dermatomyositis

In 1883, the Scots-Irish mathematical physicist and engineer usually known as Lord Kelvin wrote “When you can measure what you are speaking about and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind” (1). There is no single measure for assessing children with rheumatic diseases, which is why clinical researchers use means of simultaneously quantifying multiple disease domains. However, although it is being increasingly acknowledged that the quality of care could be improved by the routine use of quantitative evaluations (2), these have rarely been adopted in everyday clinical practice by pediatric rheumatologists.