Why is it so hard to work out the extra finance for teaching hospitals?

Teaching hospitals cost more to run than other hospitals, and since the 1976 RAWP report the NHS has paid them a supplement for it: the Service Increment for Teaching, SIFT, worth over £400m a year by the late 1990s. The trouble is that nobody knows what the right amount is. Gwyn’s work traces how the sum was set by a series of judgments rather than evidence; how nearly 90% of it went to teaching hospitals and 40% to London; and how its latent purpose became covering historic costs whether or not they had anything to do with teaching students. His 1987 comparison with Frans Rutten of how other countries organise and fund university hospitals, and his proposal to finance English teaching hospitals by capitation, set out the alternatives.