Zach Roush's Quick takes

This is a linkpost for a paper I wrote recently, “Endogenous Growth and Excess Variety”, along with a summary. Two schools in growth theory Roughly speaking: In Romer’s (1990) growth model, output per person is interpreted as an economy’s level of “technology”, and the economic growth rate—the growth rate of “real GDP” per person—is proportional to the amount of R&D being done. As Jones (1995) pointed out, populations have grown greatly over the last century, and the proportion of people doing research (and the proportion of GDP spent on research) has grown even more quickly, yet the economic growth rate has not risen. Growth theorists have mainly taken two approaches to reconciling [research] population growth with constant economic growth. “Semi-endogenous” growth models (introduced by Jones (1995)) posit that, as the technological frontier advances, further advances get more difficult. Growth in the number of researchers, and ultimately (if research is not automated) population growth, is therefore necessary to sustain economic growth. “Second-wave endogenous” (I’ll write “SWE”) growth models posit instead that technology grows exponentially with a constant or with a growing population. The idea is that process efficiency—the quantity of a given good producible with given labor and/or capital inputs—grows exponentially with constant research effort, as in a first-wave endogenous model; but when population grows, we develop more goods, leaving research effort per good fixed. (We do this, in the model, because each innovator needs a monopoly on his or her invention in order to compensate for the costs of developing it.) Improvements in process efficiency are called “vertical innovations” and increases in good variety are called “horizontal innovations”. Variety is desirable, so the one-off increase in variety produced by an increase to the population size increases real GDP, but it does not increase the growth rate. Likewise exponential population growth raise

Sometimes working on animal issues feels like an uphill battle, with alternative protein losing its trendy status with VCs, corporate campaigns hitting blocks in enforcement and veganism being stuck at the same percentage it's been for decades. However, despite these things I personally am more optimistic about the animal movement than I have ever been (despite following the movement for 10+ years). What gives? At AIM we think a lot about the ingredients of a good charity (talent, funding and idea) and more and more recently I have been thinking about the ingredients of a good movement or ecosystem that I think has a couple of extra ingredients (culture and infrastructure). I think on approximately four-fifths of these prerequisites the animal movement is at all-time highs. And like betting on a charity before it launches, I am far more confident that a movement that has these ingredients will lead to long-term impact than I am relying on, e.g., plant-based proteins trending for climate reasons. Culture The culture of the animal movement in the past has been up and down. It has always been full of highly dedicated people in a way that is rare across other movements, but it also had infighting, ideological purity and a high level of day-to-day drama. Overall this made me a bit cautious about recommending it as a place to spend time even when someone was sold on ending factory farming. But over the last few years professionalization has happened, differences have been put aside to focus on higher goals and the drama overall has gone down a lot. This was perhaps best embodied by my favorite opening talk at a conference ever (AVA 2025) where Wayne and Lewis, leaders with very different historical approaches to helping animals, were able to share lessons, have a friendly debate and drive home the message of how similar our goals really are. This would have been nearly unthinkable decades ago (and in fact resulted in shouting matches when it was attempted). But the cult

TLDR When we look across all jobs globally, many of us in the EA community occupy positions that would rank in the 99.9th percentile or higher by our own preferences within jobs that we could plausibly get.[1] Whether you work at an EA-aligned organization, hold a high-impact role elsewhere, or have a well-compensated position which allows you to make significant high effectiveness donations, your job situation is likely extraordinarily fortunate and high impact by global standards. This career conversations week, it's worth reflecting on this and considering how we can make the most of these opportunities. Intro I think job choice is one of the great advantages of development. Before the industrial revolution, nearly everyone had to be a hunter-gatherer or a farmer, and they typically didn’t get a choice between those. Now there is typically some choice in low income countries, and typically a lot of choice in high income countries. This already suggests that having a job in your preferred field puts you in a high percentile of job choice. But for many in the EA community, the situation is even more fortunate. The Mathematics of Job Preference If you work at an EA-aligned organization and that is your top preference, you occupy an extraordinarily rare position. There are perhaps a few thousand such positions globally, out of the world's several billion jobs. Simple division suggests this puts you in roughly the 99.9999th percentile of job preference. Even if you don't work directly for an EA organization but have secured: * A job allowing significant donations * A position with direct positive impact aligned with your values * Work that combines your skills, interests, and preferred location You likely still occupy a position in the 99.9th percentile or higher of global job preference matching. Even without the impact perspective, if you are working in your preferred field and preferred country, that may put you in the 99.9th percentile of job preference