Government agencies should do more to ensure that their initiatives actually result in a better level of service for the public, the National Audit Office has said.

Publishing four reports into government agencies, the watchdog warned that they need to have "sufficiently exacting targets" if improvements are actually to be delivered.

"Most commonly, these have been set by reference to past performance, but targets should also reflect changes in public expectations, and opportunities for increased efficiency, such as those offered by new technologies and innovative ways of working," said the spending watchdog.

"Targets should also reflect issues that are important for users, and there needs to be a wider range of methods to gauge what users really need and think."

The NAO found that almost three quarters of the targets reviewed in 2001/02 were achieved.

But it warned that quangos "need to give more attention to the consistent measurement and reporting of performance over time and publish reliable information on performance achievement to ensure accountability for public money".

It said that agencies "should explicitly take into account their likely impact on users and focus on aspects that deliver most benefit to users"."While agencies generally have systems in place for identifying and monitoring costs, these are not often linked to key outputs and outcomes," added the report.

"The pursuit of improved service delivery must be balanced by the need to provide value for money and agencies need to adopt more sophisticated approaches to measuring costs and productivity."

Bodies examined by the watchdog include the Veterans Agency, the Forensic Science Service and the Food Standards Agency.

The NAO found that "all have made progress in improving aspects of their performance".

The FSA had made progress towards meeting its objective to improve public confidence in food safety and standards arrangements, the report concluded.

"It can further improve by bringing greater transparency to the way in which it reaches judgements about where to concentrate its efforts and determine priorities; having better information to enable matching of resources to its workload; and adopting a more systematic approach to assessing its impact on food safety and standards," added the watchdog.

Sir John Bourn, head of the NAO, said the reports had carefully examined the government's key aim of improving the delivery of public services.

"We have found many examples of good practice in the organisations we have examined in detail.

"We have brought these together into one report so that agencies can learn from the success of others," he said.