Charities often prompt supporters with gift values but don’t analyse the results because they’ll never know what the response rate might have been. I think all you really need to evaluate prompts is an understanding of gift distribution.
In this real-life example, donors who give (on average) less than £40 received an appeal with prompts of £18, £27, £52. This chart illustrates how the donations came in:
The prompts aren’t working. To find out why we looked at how much the donors who are responding with gifts of £10 or less usually gave. The answer: £10 or less.
Based on this, we’ve created a new segment for donors who give £10 or less. This year, these donors will get prompts of £5, £10, £20. The objective, to increase response rate.