Attrition rates for fundraising methods other than face-to-face should be published, according to the Public Fundraising Regulatory Association.
Michael Naidu, vice-chair of the PFRA and assistant director of fundraising at Mencap, said face-to-face fundraising was the only method that accurately reported and published attrition rates.
"As a charity that has recruited regular donors through direct mail, DRTV, press adverts and door drops, as well as face-to-face, it would be really useful to have the same kind of intelligence for other types of fundraising as we do for face-to-face," he said.
"PFRA members are leading the fundraising sector in modelling donor attrition, and other methods of fundraising would do well to follow our lead."
The PFRA is calling for members to submit data for its fourth Donor Attrition and Retention Survey. The survey measures how quickly donors recruited through face-to-face fundraising cancel their regular donations.
Alistair McLean, chief executive of the Fundraising Standards Board, said it was good that the PFRA measured attrition rates but he assumed that all good fundraising directors would be aware of attrition rates for all types of fundraising.
"Being on top of donor attrition is important, just as cost of acquisition is," he said. "All charities involved in fundraising would seek to secure the highest level of return on their investment."