Potential consequences of the UK Research Excellence Framework (REF) for US job prospects In answer to a question about moving between employment in the UK and the US, user StrongBad suggests that "the obsession with the UK REF will likely push your CV in directions that are not ideal for getting a job in the US."

This point struck me as interesting, as in some respects it appears counter intuitive. When I asked why this was the case, he suggested that it would make a good question. I'm now asking that question.

For those unaware of the REF, it is a regularly occurring (and not uncontroversial) nationwide assessment exercise which is used to guide the distribution of funding amongst UK universities.

In order to perform well in the REF, there is a pressure on researchers in the UK to produce a number of publications (four, to be precise) which are deemed to be of a high level. In assessing quality, reviewers are guided to consider whether a piece of work is "world-leading in terms of originality, significance and rigour". Furthermore, since the most recent REF another consideration for assessment has been whether research has "an effect on, change or benefit to the economy, society, culture, public policy or services, health, the environment or quality of life, beyond academia."

What's therefore not clear to me is why would building a CV containing publications deemed by peers to be world-leading, and conducting research which peers deem to have benefit outside of academia, not be ideal for job prospects in US academia?
The REF credits departments for grant capture and not the individual. This means that large grants with multiple PIs tend to be prioritized over smaller grants to individuals. In terms of the US job market, being able to demonstrate grant capture at the individual level is important in many fields. For example, generally in the US being the only PI on a $200,000 grant is viewed better than being one of ten PIs on a $5,000,000 grant. 

The REF "requires" academics to "produce" 4 high "quality" publications over a 4 year period. Only the 4 "best" publications matter. This results in a push for splashy, as opposed to solid, research. The goal for the REF is to make your work look important to people peripherally related to your field and not the people who specialize in your subarea. Authorship across the 4 publications can also be shared so teaming up with a more senior colleague and being a secondary author is very desirable for the REF. For the REF, someone who is a co-author on 4 Nature papers with colleagues at different universities, and nothing else, could easily get a position as an associate professor, if not a full professor. In the US, search committees want to see a body of solid work that is clearly done by the applicant.

Being able to demonstrate impact is also important for the REF. This requires wider engagement with people outside your field. Having research that can be link to a "change in process" is key for the REF. For example, a clinical trial that shows X is better than Y would be considered "high impact" while the development of X would have less impact. Blue skies basic research has essentially no impact and is discuraged. US job searches do not really care about impact.