By high school I was very into altruism, but it took me a lot longer to discover the effectiveness piece. Some ideas I wish I had heard about then:
Effects matter more than personal virtue (it's better to accomplish something than to just have good intentions.)
Different projects and charities produce different effects, and it's important which ones you choose.
You may want to study things beyond typical do-gooder subjects (anthropology/sociology, foreign languages, etc.) Subjects like economics aren't just for greedy/selfish people - they can help you help other people.
As a data point, I derived some parts of the effective altruist idea cluster during my senior year of high school. The parts I understood then were that earning to give was a way to help people efficiently, and that it wasn't something I should look down on. (I'd grown up with the idea that helping with money without getting your hands dirty meant you weren't a good person - I don't know where I'd gotten that from.) This was triggered by seeing a presentation at school by a charity that said they were a good one because they could help more people with less money (I hadn't connected the ideas of charity and efficiency before that), and trying to figure out what to do with my career after high school and what to do with my morality after becoming atheist at around the same time. I didn't really think in terms of finding the most efficient charity, but I remember attempting to do that using one of those charity overhead websites and giving up because I couldn't find useful information.
I don't think effective altruism should be hard for most high school students to understand the basics of. The difficult part is that no one else is talking about charity that way, so it's hard to come up with on your own. Whether they'll accept the idea is a different problem, but I imagine at least some would like it for the reasons I did (wanting to do good, and wanting to follow one of the earning-to-give sort of careers anyway), or like it because it's contrarian. High school is when most American students are thinking about choosing a career, so it's probably good timing, too.
I'm already plotting out a story that's sort-of effective altruist fanfic, but it's set in A Tale of Two Cities, which isn't very popular with fanfic readers. (The story is about a minor nobleman trying to help his village through famines and other problems. The main EA-related themes are making sure your helping is efficient and actually works, and that you should use your privilege for good. I can go into more detail if anyone is interested.)
I'm not sure what a good EA fic would look like, especially if it's the earning to give angle. It seems a little tricky to make a dramatic story about that, because the donor (who I assume would be the protagonist?) is distanced from the people they're trying to help, and money is one of the least interesting forms of power to read about. Making the protagonist's circle of concern or circle of influence smaller, or writing a pair of characters with one earning to give and one on the front lines, would help with that.
The cluster of ideas underlying effective altruism is an important part of my worldview, and I believe it would be valuable for many people to be broadly familiar with these ideas. As I mentioned in an earlier LessWrong post, I was pleasantly surprised that many advisees for Cognito Mentoring (including some who are still in high school) were familiar with and interested in effective altruism. Further, our page on effective altruism learning resources has been one of our more viewed pages in recent times, with people spending about eight minutes on average on the page according to Google Analytics.
In this post, I consider the two questions:
1. Are people in high school ready to understand the ideas of effective altruism?
I think that the typical LessWrong reader would have been able to grasp key ideas of effective altruism (such as room for more funding and earning to give) back in ninth or tenth grade from the existing standard expositions. Roughly, I expect that people who are 2 or more standard deviations above the mean in IQ can understand the ideas when they begin high school, and those who are 1.5 standard deviations above the mean in IQ can understand the ideas by the time they end high school. Certainly, some aspects of the discussion, such as the one charity argument, benefit from knowledge of calculus. Both the one charity argument and the closely related concept of room for more funding are linked with the idea of marginalism in economics. But it's not a dealbreaker: people can understand the argument better with calculus or economics, but they can understand it reasonably well even without. And it might also work in reverse: seeing these applications before studying the formal mathematics or economics may make people more interested in mastering the mathematics or economics.
Of course, just because people can understand effective altruist ideas if they really want to, doesn't mean they will do so. It may be necessary to simplify the explanations and improve the exposition so as to make it more attractive to younger people. An alternative route would be to sneak the explanations into things young people are already engaging with. This could be an academic curriculum or a story. Harry Potter and the Methods of Rationality is arguably an example of the latter, though it is focused more on rationality than on effective altruism.
However, I'm highly uncertain of my guesstimates, partly because I'm not very actively in touch with a representative cross-section of typical, or even of intellectually gifted, high school students. The subset of people I know is generally mediated by several levels of selection bias. I'm therefore quite eager to hear thoughts, particularly from people who are themselves high school students or have tried to discuss effective altruist ideas with high school students.
2. Are there benefits from exposing people to effective altruist ideas when they are still in high school?
Effective altruism as it was originally conceived has been highly focused on the question of where to donate money for the most impact (this is the focus of organizations such as GiveWell and Giving What We Can). This makes it of less direct relevance to people still in high school, because they don't have much disposable income. But there are arguably other benefits. Some examples:
Did I miss other points? Counterpoints? Do you have relevant experience that can shed light on the discussion? I'm eager to hear thoughts.
Some ideas in the post were based on discussion with my Cognito Mentoring collaborator Jonah Sinick.
UPDATE: The post provoked some discussion in a thread on the Effective Altruists Facebook group.