Thanks for all of your thoughts on this! I can speak a little to the question about metrics:
I’m curious if you’ve given any thought to dollar-weighted attrition, where you look at the total amount of money donated in year N divided by the total amount of money pledged in year N-1 for year N. (It’s possible this number could be above 100% if people underestimate how much they’ll donate.)
This isn’t something we’ve used in our impact evaluations since we’re missing donation data from around two fifths of our members (though in future we do hope to fill in some of these gaps by making it easier for members to record their donations at the point of donation). This calculation would therefore give us an estimated lower bound % of pledged money that was donated in a given year, but wouldn’t give us information about the expected contributions of members for whom we lack data. For what it’s worth, I’ve had a quick look, and, for 2014, 65% of the donations pledged for the year were recorded in My Giving.
It’d be good to hear more about your ideas for a survival analysis. If you have the time feel free to get in touch (alison[dot]woodman[at]givingwhatwecan.org)
Hi Peter,
Thanks for all of your thoughts on this! I can speak a little to the question about metrics:
This isn’t something we’ve used in our impact evaluations since we’re missing donation data from around two fifths of our members (though in future we do hope to fill in some of these gaps by making it easier for members to record their donations at the point of donation). This calculation would therefore give us an estimated lower bound % of pledged money that was donated in a given year, but wouldn’t give us information about the expected contributions of members for whom we lack data. For what it’s worth, I’ve had a quick look, and, for 2014, 65% of the donations pledged for the year were recorded in My Giving.
It’d be good to hear more about your ideas for a survival analysis. If you have the time feel free to get in touch (alison[dot]woodman[at]givingwhatwecan.org)