Lisa Fairfax has a very interesting post at the Conglomerate on whether untenured lawprofs aiming for tenure should do empirical research. Specifically, she articulates four arguments raised at a conference against such work. In very condensed form, the arguments are these: 1) it takes too long, 2) it takes a lot of work, 3) empirical articles are harder to place in general law reviews, and 4) it’s hard to get evaluations of such work for tenure purposes.
I think it’s important to note that empirical scholarship has one significant advantage for both placement and tenure purposes. A lot of traditional law review articles just rehash arguments that have been made many times before, or are essentially appellate briefs making the author’s best argument for why some policy the author dislikes should be ruled unconstitutional. The open format permits this; articles can just “explore” an issue, or can make an argument that is pretty uncontroversial or else not well supported. My sense is that empirical scholarship tends to have more discipline: the format pushes authors to frame a question that has not been answered, to try to answer it, and to discuss the consequences (and weaknesses) of the answer. My sense is that articles editors like that, and I would guess that tenure committees do as well.
Full disclosure: My first published article was an empirical study, and I have an engineering background that probably makes me less scared of numbers than most lawprofs. So actual mileage may vary.