Questions are being asked about what impact a flagship government scheme to improve the care of vulnerable patients in England will have.
The £5.3bn Better Care Fund will be launched in April 2015 to encourage greater integration between the NHS and social care.
But a review by the National Audit Office found the scale of potential savings was overstated to start with.
The government said it disagreed with the criticisms.
However, the NAO said even now, the revised plans contained "bold assumptions".
Last month, ministers championed the impact the fund was going to have after announcing nearly all 151 local plans had been signed off.
The details of the schemes vary, but all involve some form of joint working between social workers, nurses and other community staff to improve the support offered, particularly to elderly people.