The Nuffield Foundation is looking for a simple story from applicants about what they hope to achieve and how it will benefit society.
Sharon Witherspoon, director of the foundation, says: "We want a clear narrative: 'This is what I want to do and this is why it matters.' We want applicants to show thoughtfulness about their project and how it will provide a clear set of evidence."
Established in 1943 by William Morris, Lord Nuffield, the founder of Morris Motors, the foundation funds research and innovation in education and social policy. Most of its £11m annual funding goes to research by universities and individuals. It gives about £3m to charities, and says it is too small to fund core costs.
A belief in the importance of independent, rigorous research evidence and its power to bring about change is central to the foundation's work.
Witherspoon acknowledges that measuring evidence and outcomes can often be difficult in the voluntary sector, where "so much seems self-evidently good".
The foundation has four grant programmes: children and families, law in society, education, and open door, which is for projects that meet trustees' wider interests and improve social wellbeing outside the other categories.
Grants are often awarded to voluntary sector organisations in partnership with research institutions such as universities, and range from £10,000 to £300,000. Witherspoon says there are rare occasions when the foundation can award more than that.
Recent examples of grants include £79,672 to the Daycare Trust, in partnership with Oxford University's department of education and A+ education, to look at the different measures of quality applied in nurseries and pre-schools. And Gingerbread, a charity that supports single parents, was awarded £289,000 for a project to look at what the removal of compulsory Child Support Agency involvement has meant for parents.
"We judge cases wholly on their merit," Witherspoon says. "We have funded some small, local charities, but they have to be projects that have larger implications."