What is data pooling?

Data pooling is a process where data sets coming from different sources are combined.
This can mean two things. First, that multiple datasets containing information on many patients from different countries or from different institutions is merged into one data file.
Second, that data on one patient, coming from multiple sources such as e.g. primary care, specialist clinics and insurance company are combined together. In both cases pooling results in a fuller and more useful data set for scientific research.