Do R1s or PUIs have higher research expectations?
Well, of course, major research institutions (R1s) expect more research to come out of their labs than primarily undergraduate institutions (PUIs). But, after you take into account the circumstances of each kind of position, who experiences a higher relative demand for research productivity? At which kind of institution is it harder to meet the scholarship criteria for tenure?
Well, let’s compare various factors related to research productivity at these kinds of institutions*.

Here’s the downloadable and machine readable pdf of this table.
In this table, what is a PUI? I’m thinking of a variety of types of primarily undergraduate institutions, most of which are regional public universities and small liberal arts colleges. What’s an R1? Well, a major research institution. Some universities fall somewhere in the middle between a PUI and and R1. They clearly are working hard to ramp up their research game, but are R2s. There’s a fuzzy realm between regional public university and R1. And there are privates that aren’t R1s but aren’t quite PUIs. So some folks might see themselves working at some places that are hard to pin down, notwithstanding whatever designation the Carnegie folks come up with.
Now, I’ll answer the question I started with: In which kind of institution is it easier to clear the research bar for tenure? And here’s my answer: It Depends. Getting two decent pubs in a PUI with few resources and a heavy teaching load might be more difficult than getting a veritable mountain of pubs in an R1 that gives you a huge startup and access to grand facilities.
I’ve argued that what really limits productivity at teaching-focused institutions the people. Or the lack thereof. I think that argument holds up. If you’re in an R1, you’re bringing people into your sphere whose job it is to produce science. However, at at PUI, you just don’t have those people. And the people who you are with are in training to produce science and don’t have nearly as much experience. And as soon as they get up to speed, they leave. And produce in another lab.
Clearing the bar at PUIs can be way harder than at an R1. For example, it can be very do enough research to clear the bar if you’re in a PUI with poor funding and working its way up the rankings on the backs of faculty labor, with senior faculty who expect new hires to be more productive than they ever were, and unhappy administrators looking for cheap fixes to jump ship. And the whole while, you realize that the slightest slide in your teaching evaluations might raise some eyebrows, even if those changes have nothing to do with how much students are learning. On the other hand, if you are in an institution that expects a huge amount of research, but you’ve gotten lots of startup funds to hire a crack team and you have lots of resources available, and low teaching requirements with simple preps, then perhaps it would be easier to clear that bar. It also depends on the kind of work that you do. Some kinds of work are harder to do at PUIs than others.
When I say “it depends,” I’m not saying this as a cop out. I’m saying It Depends because it’s the conditions on the ground at any given institution that matter more than the institution type. It’s not easier at PUIs, just different.
Some grad students look at the tremendous pressure that their PIs are under, and will think, “Gosh, I love research and teaching but I don’t want to have to live with that kind of stress!” and then wind up taking jobs at PUIs that are just as difficult and stressful. Some R1s are very good about making sure that the faculty there lead normal lives, and are subject to reasonable expectations, and some are horrible about this. The same exact thing is true of PUIs. And you won’t know this until you get close to the institution. It could possibly take you years to figure this out about a particular institution, because some departments are good at deceiving others and themselves about the existence of a toxic culture.
As in so many other things, the details will make the generalizations downright useless.
*Where did everything on this table come from? I could fish out citations for a few (and I just asked folks if my startup estimate for R1s was okay and also looked at job wikis and papers about this), but for many of the categories, it’s me pulling from experiences and conversations. There are a couple that I am quite convinced about, but for most of them, I’m sure you have a differing opinion that can be just as good as my own.