No big data without small data: learning health care systems begin and end with the individual patient.

Abstract

The apparent contradiction between the population focus of big data and the practice of personalized medicine contributes to the relatively scarce and slow applications of big data in medicine compared with other areas of knowledge. The technologic development and the implementation of EMRs may give rise to a learning health care system in which every doctor–patient encounter becomes the connecting link between the population and the individual. To generate valuable knowledge, big data must come from high‐quality individual clinical data. There are no big data without small data. EMRs may be used to integrate research into medical care, thereby conducting point of care research (e.g. randomized database studies). However, big data will not achieve its full potential if it is not used to improve health outcomes for the individual patients from whom the data were generated. EMRs should aid doctors in personalizing medical care and contribute towards the engagement of patients in research and care. The continuous interaction between the individual patient and the population, between clinical research and medical care, between the world of big data and that of small data is an essential step towards achieving a true learning health care system.