Setting performance targets for doctors charged with bringing down patients' blood pressure and rewarding those who get there is not an effective motivator, according to researchers at Harvard University and the UK's University of Nottingham.

One of the lead researchers, Stephen Soumerai, said in a statement that there was relatively little difference between doctors who were paid for high performance and those who weren't.

"The study found that good quality of care for hypertension was stable or improving before pay for performance was introduced. Pay for performance had no discernible effects on processes of care or on hypertension related clinical outcomes and the system may not be sufficient to improve quality of care and outcomes for hypertension and other common chronic conditions," he said.

Soumerai went on to add that it's likely health insurance companies and governments are both wasting large amounts of money on such programs for a highly questionable return.

It's unknown, as yet, what kind of effect the study will have on pay-for-performance programs in either the UK or U.S., experts say.