What are filters and amplifiers and how do they impact your regular giving appeals? In this must-read post by Chris Keating, he covers the late Prof. Siegfried Vögele’s approach and the principles behind direct marketing. https://medium.com/@chriskfundraising/secrets-of-direct-mail-siegfried-vögeles-dialogue-method-cda0aaca3a5e
Propper Fundraising 