I have to disagree with the "small effects" crowd.

Putting aside any notions of justice (which I suppose is implied), this depends on what you mean by "economic welfare." A perfectly tuned definition of economic welfare could encompass the economy's ability to satisfy the needs and desires of all of its people, but we tend to use simpler measures, such as GDP.

If you mean something like GDP, the manner in which such a value increases has an enormous impact on resultant human welfare; particularly on who the benefits flow to. A huge element of this is because of the marginal utility of goods; if you already make $50,000 a year, an additional $1,000 will not have nearly the same impact on your well-being than it would someone who usually subsists on $500. This is one of the central (usually implicit) premises of Give Directly, and perhaps all charity.

The disproportionate reduction of suffering, increase of satisfaction, and avoidance of alienation brought about by a more equal distribution can only be described as "small effects" by those whose material needs were long since fully served, and have little empathy for the less fortunate.

If your goal is merely to increase total economic capacity with no regard for who or what that flows to, your best bet is likely to fund first-world business ventures and research institutions. But maybe you should drop the "altruist" label at that point.

I've never been more worried about this movement.

Last year I directed most of my donation to GiveWell without restrictions, because I feel our goals overlap to the extent that I was comfortable with them serving as my proxy and/or using the funds to further their research and advocacy.

I believe GiveWell has to be relatively circumspect about self-promotion in order to avoid undermining their credibility with skeptical consumers of their research.

I'd give to them if you trust them as much as you seem to, and don't disagree with the premises of their analysis sufficiently to want to tweak the dollar allocations. They expend a lot of mental effort trying to avoid completely overriding the preferences of their influenced donors (for example, if you want more money to go to SCI and less to GiveDirectly).

Agree with the general advice, and I'm particularly intrigued by the idea of how EAs should be less risk-averse than the general population, or should otherwise adopt different strategies than other rational investors.

You speak of how we can get very similar value by buying the Nth vaccine (versus the Nth car), which makes a lot of sense. Another approach would be to just save less, hold these minimal retirement assets in safe instruments, but give the remainder to an organization or your own charitable trust earlier in a very aggressive manner.

I have this vague idea that it's probably best to save until an aggressive high-stock portfolio that performs particularly poorly could still cover expected lifetime living expenses, and then to give away any additional funds over and above this amount.

Probably the biggest drawback to this approach is that it invites the temptation to consume excessively. It may be better to starve ourselves of this excess capital by signing it over to the organizations we most trust.