To echo what gwern said, AFAIK actuaries are only useful insofar as there's a large data set for them to work with. Often when evaluating evidence, you need to evaluate the merits of a bunch of studies and aggregate them along with any non-scientific evidence (e.g. not published in peer reviewed journals, not statistical, etc.) you may have, and this isn't what actuaries do. What you need is a statistician with specialist knowledge in the field(s) you're interested in. Or a specialist with some knowledge of statistics. These people are often called scientists.
It occurred to me this morning that, if it's actually valuable, generating true beliefs about the world must be someone's comparative advantage. If truth is instrumentally important, important people must be finding ways to pay to access it. I can think of several examples of this, but the one that caught my attention was actuarial science.
I know next to nothing about what actuaries actually do, but Wikipedia says:
Why, that sounds right up our alley.
So what I'm wondering is: for those who can afford it, wouldn't it be worth contracting with actuaries to make important personal decisions? Not merely with regards to business, but everything else as well? My preliminary ideas include: