Nathaniel Whittemore’s Social Entrepreneurship Blog asks bloggers for “one thing you need to know before you donate to charity this holiday season.” My answer: you need to know that your favorite social program might just not work.

This isn’t a warning against fraud or inefficiency (though both of those are important too). It’s a warning against programs that just don’t change people’s lives in the way we hope – even if they seem to make perfect sense, and even if they’re carried out perfectly.

The first $17,000 I ever donated (personally) was to programs that I now believe don’t work. During my years in the finance industry, I gave to the best organizations I could find for improving education (jr. high and high school) in NYC.

I considered education my favorite cause. I assumed that equality of schooling was the key to equality of opportunity. I didn’t have the time or the energy to question this assumption. I now believe this assumption is badly wrong, for reasons that are outlined here.

I wish I could take that money back: de-fund the “small schools” and extracurricular activities I supported (both of these are programs I now know to have very questionable, if not negative, track records) and instead fund programs for early childhood (where I believe inequality of opportunity really begins) or international aid (where it’s far more drastic).

I wish that money had gone to organizations that I really believe are changing lives in a significant and lasting way, but it didn’t. Please don’t make my mistake.

There are great-sounding programs out there, based on one theory or another of what the roots of poverty and opportunity are. When put under the microscope, many of these great-sounding programs just don’t work, most likely because they simply didn’t take the right approach to the complicated problems they’re trying to solve. Many more of these programs are unexamined and unproven.

Charities that will put your money into proven ways of helping people are the exception, not the rule. They’re not necessarily easy to find. They’re not necessarily the same ones that knock on your door and get your friends excited. This season, with or without GiveWell’s help, I hope you find one.