From a fundraiser's perspective - what do Effective Altruists want to see from 'other' charities?

I am normally a bit distrustful of any cause areas or charities that claim it is too difficult to quantify impact or calculate cost-effectiveness. 

Phrases like "the work is complex" or "data is difficult to collect" are kinda red flags to me, not because they are untrue, but because:

• they are also true of a huge number of charities and cause areas for which EAs are able to make estimates. (These estimates might be super uncertain, and have big error bars, but they are better than nothing).
• And because, I suspect, the actual cost-effectiveness is often likely very low, even a highly uncertain CEA would point to that, and thus excuses like "it's too complex" are used to avoid having to confront that.

I am instantly more trustful of any charity or cause area that attempts to estimate their cost-effectiveness, especially if they have strong reasoning transparency and highlight their key uncertainties and suspected error bars.

• AIM / Charity Entrepreneurship, for example, estimates cost-effectiveness for advocacy ideas - these are extremely hard to do accurately and have massive uncertainties. They are also very much reliant on others and it is impossible to specifically isolate the charity's impact - nonetheless, they provide a transparent, good-faith estimate. (e.g.)

There's a shortfall of evidence around the topic of human trafficking, which my colleague explores in this report on human trafficking. Innovations for Poverty Action explores this in some new reports here, and here.

My sense from a cursory overview of the problem and tentative solutions: human trafficking is an important cause (comparable in scale (DALYs) to a problem like maternal disorders, but the solvability is of much lower confidence than for problems of similar or greater significance, such as malaria deaths. 

For instance, evaluators have strong confidence -- based on lots of robust academic peer-reviewed and RCT evidence -- that we can prevent a death by malaria for $3-5k. 

We don't have comparably strong evidence for preventing human trafficking (and if there is, I'd love to see it!)

It might be helpful if you could share what types of data you are able to collect, and your best-effort at producing a BOTEC for your cost-effectiveness so far.