In particular, there might be ways for Rethink Charity to expand the EA survey to gather more rigorous data on value drift (selection effects are obviously problematic – the people whose values drifted the most will likely not participate in the survey).
An easy way to gather a pool of “value drifted” people to survey could be to look at previous iterations of the EA survey and identify people who filled out the survey at some point in the past, but haven’t filled it out in the past N years. Then you could email them a special survey asking why they haven’t been filling out the survey, perhaps offering a chance to win an Amazon gift card as an incentive, and include questions about sources of value drift.
An easy way to gather a pool of “value drifted” people to survey could be to look at previous iterations of the EA survey and identify people who filled out the survey at some point in the past, but haven’t filled it out in the past N years. Then you could email them a special survey asking why they haven’t been filling out the survey, perhaps offering a chance to win an Amazon gift card as an incentive, and include questions about sources of value drift.