We are pleased that the Department of Health has finally committed resources to the GP Research Database (news focus, pages 12-13, 12 August).

Contrary to the cartoon accompanying your article, the database has only ever had two owners, VAMP and the DoH. Management of it has now been transferred to the Medicines Control Agency from the DoH statistics division. The Office for National Statistics' GPRD department has been responsible for collecting and validating the data since its transfer to the DoH, and it will continue to do this under the MCA's guidance.

We are not aware of the extent of Dr Paul Cundy's experience with the database, nor can we definitively 'prove' the usefulness of the information collected. But a list of over 100 publications, with many more in the pipeline, is available from our offices. More than 250 studies have been conducted on the database in the past five years, many by doctors and academics eminent worldwide. This may not prove its usefulness for Dr Cundy, but someone in the DoH has been convinced enough to assign£3m to its development.

The database does not contain a forced link between prescription information and medical diagnoses. It does contain a temporal link similar to that in any manual medical record system, which it is designed to emulate, and adds to the real-world aspect of the data. Analysts need clinical knowledge when working with the data. Systems containing a forced link can produce inaccurate interpretations without expertise in UK general practice.

The database contains over 250 million prescriptions, of which 1.8 million are penicillin. All data entered is validated by a highly experienced team at ONS. Practices have to achieve very high recording standards before their data is included. The current standards for therapy records are that a minimum of 85 per cent of acute prescriptions must have a medical entry on the same date; 85 per cent of new (acute and repeat) prescriptions must have a medical entry on the date of the first prescription. In practice, over 90 per cent of all prescriptions are recorded on to the system.

The database is the largest, most validated and most widely used GP database in the world.

Dr Alan Dean