Donors can complain about quite a few things you might do, from spelling their name wrong to sending them mail while they were on vacation.
But there are a few things donors never complain about, including: “It’s Too Easy to Read!” The One Complaint I’ve Never Heard from a Donor (on The Better Fundraising Blog).
Some fundraisers "bulk up" the readability of the communications because they believe their donors are "more educated" and/or will bristle if "talked down" to. So they use long, complex sentences and technical terminology.
Which is a big mistake, no matter how highly educated and intelligent the donors are.
Because even the most towering intellectuals among donors don't notice that you're aiming up at them to recognize their achievements.
They just become less likely to respond when your message is harder to read.
Thing is, you'll also never hear a donor complain that your fundraising message is too difficult to read.
They don't notice that either.
Paying attention to readability is a responsibility of writers. Readers don't note the ease or difficulty of any text.
But if it's easy, they are more likely to read. If they read, they are more likely to respond.
And if it's difficult, they are less likely to read. Thus less likely to respond.
The correlation is clear.
But no complaints come in, either way.
If you want maximum response, make your message easy to read. That means two things:
1. Keep reading ease good, typically a Flesch–Kincaid grade level of 6 or lower or a score of 80 or higher.
(Yes, it's a bit confusing. There are two Flesch–Kincaid ways of measuring readability. Grade level, where lower numbers mean easier, and score, where higher numbers mean easier.)
2. Design for readability. That means large fonts (12 point should be the minimum), readable fonts (usually serif fonts in print), plenty of white space, short paragraphs, and no design tricks like reverse type or colored type.
Either way, complaints aren't going to clue you in that you've made an error of readability.
Response will show you. Hard to read = less response.