Hello Blake, There's lots of questions to ask and answer here, but I will give some brief pointers on one aspect I think is important:

How do you think I should judge success? QALYs? How would I even judge QALY improvement?… In the end, I want to be able to say $5k to a family of 5 reduces suffering by a factor of X. I hope to compare these measures to EA giving opportunities.

This is a question about how to define and measure the 'good' that an action will do. Different charity and intervention evaluators have recently presented how they do so, here on the forum.

At the Happier Lives Institute - where I am a research analyst - we use subjective wellbeing / WELLBYs. This will capture 'good' better and broader than QALYs or other measures. See here for our case for the WELLBY. We've reviewed AMF, deworming, GiveDirectly, and StrongMinds using subjective wellbeing (see our 2022 recommendations here). We've even considered household spillovers for cash transfers and psychotherapy.

I think this measure, or at the very least ours and other works in subjective wellbeing, will be very relevant. I'm happy to chat more about this.

Hi Blake! Thanks for the thought-provoking post, and thank you for your generous donation. I appreciate and sympathize with your desire to quantify the impact of your gift into one tidy figure (e.g. QALYs/$). However, in this case, it might useful to base your impact assessment on more than one figure.

You may consider looking to GiveDirectly as an example. The organization frequently reports impact/dollar, but they do so in many ways. In some studies, they focus on psychological wellbeing, in others food security, and in yet others educational outcomes. In each report, they measure many kinds of results using various methodologies and are also sure to look for potential negative impacts. 

The lesson is that overall well-being has many complex inputs, and especially with small sample sizes, cannot be easily distilled into one figure. Your donation is but one factor in these children's complex lives. I wouldn't be surprised if, as a result of your gift, some aspects of their lives improve while others worsen. This is precisely why organizations like GiveDirectly perform studies with hundreds of participants.

I am no expert in social work or impact quantification, but I do know that what makes human lives go better is quite nebulous. The results of this cash infusion unfortunately won't go far to predict the results of the next intervention, even if it looks similar.