Doctors from a number of European countries have been collecting data on their patients separately, and they would like to pool the data together, in order to allow them to review the data and extract information on the European experience on a particular treatment in a retrospective manner.

Unlocking the Power of Data

The original data collected and entered by the doctors were stored in a variety of formats eg Excel spreadsheets, Access databases, SPSS datasets etc; and these data were not defined and collected in the same way by the doctors.

Without changing the data collection method already established at each doctor's institution, we proposed mapping the data into a common data structure, using the following steps:

1. Identify what analyses will be required, and what variables will be needed.
2. Define the common database structure, and the process of populating and updating the database.
3. Review the database from each doctor, and work out how each variable and its values can be mapped into the common database structure - this is documented in a mapping specification document.
4. Write computer codes to extract the data from each database, perform some checks on the validity of the data, transform (or "map") the data into the common database structure, and the upload them onto the common database.

Enhancing Knowledge and Performance

Data have been mapped and pooled together successfully, and the pooled data have been analysed on several occasions, with data published in journals and presented in conferences. This allows the doctors to share the knowledge and experience with their peers and colleagues around the world.

This initiative also helps to promote knowledge sharing among this group of doctors.