The effectiveness of an incentive scheme aimed at reducing the number of youngsters leaving school early has been questioned.
Ministers are trying to encourage pupils into further study
Research commissioned by the Scottish Executive has indicated that most of those who stayed on would have continued their education anyway.
The Educational Maintenance Allowance (EMA) was brought in three years ago.
The weekly payment of £30 is offered to 16 to 19-year-olds from low income families.
A study for ministers found that the EMA was "not an influential factor for the majority of young people".
The report investigated the impact of the allowance on preventing youngsters from missing out on education and training opportunities.
The report said: "The majority of EMA recipients were studying Highers and had planned to stay at school regardless of EMA."
The youngsters the scheme hoped to attract were already "absenting themselves from school or were disillusioned with education and had already left school".
The review prompted Tory children, schools and skills spokeswoman Elizabeth Smith to call on Education Secretary Fiona Hyslop to rethink EMA.
She said: "With the scheme costing the taxpayer £42.8m for each academic year, the results of the study are a matter of concern.
"It is clear that the EMA is not having the desired effect since it is failing to target the many youngsters in deprived areas across Scotland who leave school with no clear educational, employment or training future."
Judith Gillespie of the Scottish Parent Teacher Council said the sceme had been more successful in colleges than in schools.
"It might be that blanket EMAs are not the way to go," she said.
"There are a lot of important messages that need to be looked at carefully. We suggest that the college money is working effectively but continuing it with schools may not be the way to go."
The Scottish Executive said it was pleased the scheme had managed to improve attendance among some pupils but said it would be studying the report's other findings.
More than 40% of 16-year-olds are thought to receive the allowance in Scotland.