Why I'm skeptical of cost-effectiveness analysis


  • The entire course of the future matters (more)
  • Present-day interventions will bear on the entire course of the future, out to the far future
  • The effects of present-day interventions on far-future outcomes are very hard to predict
  • Any model of an intervention's effectiveness that doesn't include far-future effects isn't taking into account the bulk of the effects of the intervention
  • Any model that includes far-future effects isn't believable because these effects are very difficult to predict accurately


I want to think more about this – if you see a place where my reasoning is wrong, drop me a line.

Comments (4)

Comment author: kbog  (EA Profile) 04 July 2018 12:09:54AM *  2 points [-]

I disagree with 5. Under subjective probability theory it is not really coherent to think that one's expectation is inaccurate. You probably mean to say that they are difficult to predict precisely, but that's generally not relevant if we are maximizing expected value.

Comment author: Milan_Griffes 04 July 2018 12:32:44AM 0 points [-]

I'm using "accurate" to mean something like "well-calibrated" (a person being well-calibrated if e.g. their 20%-likely predictions come true 20% of the time).

Another way of phrasing (5) is that it is very difficult (maybe impossible?) to become well-calibrated re: the far future.

Comment author: Peter_Hurford  (EA Profile) 04 July 2018 03:15:18AM 0 points [-]

I'm not sure if (2) is wrong or not, but I'd guess it tends to be overemphasized. For example, if I went back in time 100 years ago and gave the poorest person $1000, would the aggregate indirect effect over those 100 years really be bigger? I'd like to see more argument for this one way or another.

Comment author: Denise_Melchin 04 July 2018 10:37:53AM *  0 points [-]

(Denise as mod)

The EA Forum is a place for high level discussion on EA matters which are often too long or inappropriate in other spaces like Facebook. Not yet fully fledged or thoroughly argued ideas are better placed there, since the EA Forum gets too crowded otherwise.

Therefore I'll delete your post. You can modify it and repost, or alternatively, post it elsewhere (like the EA Hangout Facebook group).

Edit: All further comments will be deleted.