I found this NBER working paper interesting, though after some thought not so surprising. It’s a well-designed study in my opinion, and they worked closely with the relatively famous group RIP Medical Debt to do the actual work. (note that this paper is specific to charitable medical debt relief that buys up debt; there may be other forms not contemplated)
Their lead-in:
There are reasons to be optimistic about the benefits of medical debt relief. Debt relief in non-medical contexts – including student loans (Di Maggio et al., 2020), credit cards (Dobbie and Song, 2020), mortgages (Ganong and Noel, 2020), and bankruptcy (Dobbie and Song 2015; Dobbie et al. 2017) – has been shown to reduce financial distress, increase earnings, and improve mental health. In a survey of experts that we conducted, most respondents predicted that medical debt relief would significantly improve mental health, financial well-being, and healthcare access.
Their conclusion, however, was that :
We estimate statistically insignificant average effects of medical debt relief on measures of mental and physical health, healthcare utilization, and financial wellness, with “opposite-signed” point estimates for the mental health outcomes relative to our prior.
A large part of that seems to be that people have already abandoned hope on their medical debts, even when they haven’t gone to collection yet.
So maybe this isn’t the best, or even mediocre-est, avenue for helping people.