The findings, which are described as an historic shift, say the change happened from about 2003, when the poverty rate for working age people improved in Scotland but did not change in the rest of the country.
The report suggests the most likely reasons for the change are a better labour market performance in Scotland and lower housing costs.
It points out that in England, the UK Government has encouraged social landlords to charge rents closer to market levels.
The Scottish Government did not follow the same policy and rents have remained more affordable, giving real benefit to lower-income households. Social housing rents are nearly 25% lower in Scotland than in England, while house prices are about 20% cheaper.
The findings were discussed at a rally in Glasgow of the Scottish Assembly For Tackling Poverty.
Delegates were told the trend was in danger of being reversed as more and more low income families are having to live in the higher priced private sector putting more at risk of poverty as incomes are eaten up by higher rents.
Nick Bailey, senior lecturer in urban studies at Glasgow University, said: "The reduction in Scotland's poverty rate is modest and comes at a time of great hardship for many families.
"Even so, it represents a real improvement and an historic break."