From paper: “Of the 4.5 million households who met the criteria for inclusion in this pilot program, 3.9 million were randomly selected to receive the intervention.”, “The final sample consists of 4.5 million returns, corresponding to 8.9 million individuals.”

Those in the treatment group were 1.3[1] percentage points more likely to enroll in coverage in the year following the intervention than those in the control group: about 50,000 extra households (~100,000 extra people) were signed up due to the letter.

So, about 200 died because they didn’t receive the letter (But that was offset by the 8 billion lives that were saved by something else that didn’t happen that day.).

[1] “those in the treatment group were 1.3 percentage points more likely to enroll in coverage in the year following the intervention than those in the control group, a 2.8% relative increase. On average, each letter increased coverage among this group by 0.14 months during 2017, or one additional year of coverage per 87 letters sent. We document larger effects among individuals who lacked any coverage during the prior year and among older non- elderly adults.”

Edited: corrected numbers - mistook households for individuals.