Before parliament dissolution, the Scottish Government stated in a document for Holyrood's justice committee: "The definition of purposeful activity … is being amended to provide flexibility in the definition and wide discretion over which activities a governor can provide for prisoners."
That could mean jails can upgrade activities that weren't previously considered "purposeful" in order to hit targets.
Freedom of Information research by the Scottish Conservatives has revealed that, last year, there were 1727 prisoners not engaged in purposeful activity – around one in five of the prison population.
A further 193 were signed off for medical reasons.
The Scottish Conservatives have said all prisoners should be given the opportunity to work while in jail, or embark on improving their education or skills.
But the FoI response from the Scottish Prison Service stated that for 7790 prisoners last year there were only 4137 works spaces and 1829 purposeful activity places.
A number of recent reports have criticised levels of work and education in jails.
The HMIPS annual report last year said: "There is still a disappointing level of purposeful activity in practice in some prisons. We found that there were too few places for work, education and training opportunities for the size of the population."
Scottish Conservative justice spokeswoman Margaret Mitchell said:
"The crucial function of prison is to ensure the public are kept safe.
"But equally important is the rehabilitation of offenders and tackling the barriers, including literacy and numeracy problems, which prevent prisoners from finding gainful employment when they are released.
"That's the right thing to do for them, and for the wider society who will benefit from them being less likely to re-offend.
"But making it easier for prisons to say they are providing purposeful activity without specifically linking this to work, training, education or addressing addiction issues is not the way forward.
"At present the demand for this kind of rehabilitation far outweighs supply.
“Given this the extension of this vague term, purposeful activity serves merely to ensure the SNP majority government is hitting a false target.
“The public fully expect purposeful activity to be exactly that but with these plans, who knows what could be considered productive, maybe even playing pool or darts?"