Usually, the more popular and publicised the cause the shorter the letters can be. But as a general rule, short letters communicate, but long letters raise money.

Extensive testing by a wide variety of charities shows that long copy wins most of the time, especially for prospect mail and emotional house appeals. Of course, there are exceptions and it’s always best to test.

Board members will usually say, ‘Our donors are too busy to read long letters’. They don’t understand that people who are too busy to read long letters usually don’t give much money.

That depends. There is no such thing as a standard length. About 80 per cent of the time, a multiple-page letter out pulls a single-page letter. About 50 per cent of the time a four-page letter out pulls a two-page letter.

To understand why long letters work sometimes and at other times short letters work we have to explore several subjects.

Getting the attention of your reader is just a first step. To be successful, you have to keep the reader’s interest until a positive decision has been made.

Human inertia is a negative force: it’s easy to do nothing. One way to defeat inertia is to get your reader involved. You have to keep your donor thinking about your problems until she is convinced and ready to say ‘yes’.

Short messages do a better job of communication, but extensive testing shows that, except in special circumstances, short messages fail to move the reader to action.

Why? Probably because without involvement (see above) you really don’t have the reader’s full attention.

A short letter may work if the reader knows about the charity. For example, a major, well-publicised charity, such as the Red Cross, or CARE, is already identified in the reader’s mind.

The general rule seems to be that the more ‘popular’ or ‘visible’ your organisation, the shorter your prospective donor letter can be.

letter often works. For example, it doesn’t take much copy to communicate the need for medical aid to save suffering children.

But if your appeal is more complicated, then logic is involved and logic is tough to sell with short copy. To communicate a logical appeal you often have to illustrate it in several ways and this takes space and words.

After a terrible earthquake or hurricane some of the strongest appeals may be half-page telegrams. The public already knows about the disaster and it doesn’t take many words to communicate the need for helping the earthquake victims.

Sometimes a ‘dear friend’ letter is more cost efficient than the standard personalised letter. However, when a computer-personalised letter does work, the shorter format is usually more cost effective – provided that the letter contains personalisation other than just the name and address of the donor.

If you mention the amount of the donor’s last gift, the personalisation is often strong enough to make a shorter letter work.

If for some reason you can’t test then you’d better play the odds and err on the side of the multiple-page letter. But remember, long copy means tight, compact copy moving the reader toward a final climax and a ‘yes’ decision.

© SOFII Foundation 2010-2014.