The Impact Review, which follows a trail blazed by the RNID, has been sent out to stakeholders and potential donors to showcase what the organisation has achieved for its beneficiaries in the past year.
It's the first time Mencap has put together an accountability review, which has been released to coincide with its annual report (March 2001-2002) and incorporates around 30 case studies of projects that the charity has run to help people with learning difficulties.
"It's a more comprehensive overview of the different ways of making an impact on the number of people we're reaching, together with the qualitative aspect of the monitoring and measurement of our performance," said David Scott-Ralphs, Mencap's director of strategy. "We're painting the human story - it's not just facts and figures."
Luke FitzHerbert, a researcher at the Directory of Social Change, said: "It's extraordinary that every charity hasn't always had a review of this kind."
The charity has also produced a seven-page document called A Guide to Mencap's Accounts, which uses large type and also aims to make the figures more accessible to people who have learning difficulties.
"The RNID set a challenge to the rest of us," said Scott-Ralphs. "Their Impact Report gives a lot of detail in terms of facts and figures about what it's trying to achieve, whereas our Impact Review is more a year of achievement for people, through the words of the individuals that we help. It's not costly to do and we hope to do it every year."
As part of the review, a new customer-led approach is to be introduced, which will involve care staff engaging with service users. In turn, the information gathered will be collated centrally to help the charity be more "proactive" in its approach.
Another proposal by the charity is to create service user forums to localise their approach which will be run by the charity's community support teams.
The customer strategy will be backed up by the appointment of a number of external bodies including the Telephone Helpline Association, which has been commissioned to benchmark Mencap's current performance across their helpline services, in a bid to strengthen their proposition.
"We're being more systematic in information capture and building databases based on customer initiatives," said Scott-Ralphs.