But insofar as the lottery enhances the effectiveness of donors (by letting them invest more in research if they win, amortized against a larger donation), then you want donors doing good to be enhanced and donors doing bad not to be enhanced. So you might want to try to avoid boosting pot size available to bad donors, and ensure good donors have large pots available. The CEA lottery is structured so that question doesn’t arise.
There is also the minor issue of correlation with other donors in the same block mentioned in the above comment, although you could ask CEA for a separate block if some unusual situation meant your donation plans would change a lot if you found out another block participant had won.
Yes, the main effect balances out like that.
But insofar as the lottery enhances the effectiveness of donors (by letting them invest more in research if they win, amortized against a larger donation), then you want donors doing good to be enhanced and donors doing bad not to be enhanced. So you might want to try to avoid boosting pot size available to bad donors, and ensure good donors have large pots available. The CEA lottery is structured so that question doesn’t arise.
There is also the minor issue of correlation with other donors in the same block mentioned in the above comment, although you could ask CEA for a separate block if some unusual situation meant your donation plans would change a lot if you found out another block participant had won.