Isaac Opper
imopper.bsky.social
Isaac Opper
@imopper.bsky.social
Senior economist at RAND
@jessebruhn.bsky.social, Sai, and I are almost done with a paper that jointly estimates teacher VA and school VA. We're finding (in NC) school test effects of about .08 student SDs and that ~30% of that is due to variation in avg. teacher quality across schools.
October 9, 2025 at 5:21 PM
It's not quite that, but I believe Bruce Sacerdote has a study using random adoption matching to get at it a bit.
December 18, 2024 at 4:51 PM
"You either play hide and seek with me now, or pay for my psychologist in 5 years. Your choice daddy."
December 18, 2024 at 4:47 PM
Isn't "fucking around at margins" more or less the definition of economics?

(Also, stop trying to guilt me to spend more time with my kids. They're good enough at that on their own, thank you very much.)
December 18, 2024 at 4:22 PM
It's not just a question of "which matters more" from a causal inference sense but also "which can we use public policy to improve," no?
December 18, 2024 at 4:19 PM
I've always wanted to meet the magical whiskey fairy. I'm ashamed to admit that I even started to doubt whether she actually existed, but you've given me hope Jesse.
December 6, 2024 at 2:39 AM
I think a big part of it is that it's really hard to separate teacher effects from school effects, which you need to do if you really want to understand sorting. I'm working on a paper that tries to do that, in part to answer the sorting question, but it's a tricky empirical question.
December 5, 2024 at 9:55 PM
4/ What makes me most excited about this work is that I think it can also be a useful building block for estimating effects in other complicated settings, such as averaging RCT and non-RCT estimates, RDs, judge IVs, etc.

So definitely let me know what you think of it, good or bad!
December 4, 2024 at 10:45 PM
3/ Even more interesting, it turns out we can decompose the resulting posterior variance into that generated by traditional statistical uncertainty vs extrapolation uncertainty.

Much to my surprise, even in the huge Oregon Medicaid experience the statistical uncertainty seems to dominate.
December 4, 2024 at 10:45 PM
2/ The basic idea is that by adding a Bayesian hierarchical model to traditional econometric models of selection, we can generate estimates/CIs of the ATE (or other estimands) that capture uncertainty in both the true values of the observed moments and uncertainty in how to extrapolate from these.
December 4, 2024 at 10:45 PM
Isn't it partly a question of what you hold fixed and what is considered random when thinking about inference? E.g. if the size of spillovers depends on who is grouped, then it depends on treatment assignment and so cluster? If not, then they're fixed and so you don't need to cluster?
November 25, 2024 at 5:01 PM
Oh wow, I hadn't even heard that!
November 20, 2024 at 1:26 AM
See there's the difference between us: unlike you, I haven't gotten a grant in a while, but this was 100% me after putting my toddler to bed last night.
November 20, 2024 at 1:14 AM