It is difficult to evaluate a growing organization such as Giving What We Can, because the fruits of work performed today may not be seen until the future. As a simplifying assumption we look at the expenses and achievements of Giving What We Can through a given date, but we assume members will keep their pledges for some period of time so that the total good expected to be done gets counted. This is different than our evaluation of GiveWell which does not have members making pledges, and so we more conservatively assume for GiveWell that the benefits from one year's expenses are born out by the fruits of the following year.
Giving What We Can publishes a fundraising prospectus. The 2015 prospectus makes a number of reasonable assumptions to come up with the estimate that $1 given to Giving What We Can will translate into the equivalent of $60 going to their top charities.
We use previously made estimates of the leverage factors for their top charities:
|Assumed donations||Estimated leverage factor||Notes|
|Against Malaria Foundation||25%||2,500 - 20,000|
|Schistosomiasis Control Initiative||25%||1,100|
|Deworm the World||25%||1,100|
|Project Healthy Children||25%||unknown||Assume leverage factor equal to average of other charities|
This allows us to produce the following estimate.
|Project||Cost||Real world outcome||Outcome estimates||Economic value in Western terms|
|Giving What We Can||$1||$60 moved to top charities||-||$96,000-444,000|
100,000 - 400,000