And what Connors reports has a bit of the feel of a good news/bad news joke. The good news is that he cites a number of empirical studies that seem to validate the assumption that sentence-based writing pedagogies do indeed improve writing—and do so rather dramatically. The bad news is that they have fallen out of fashion, precisely in part because of a larger suspicion in English studies of empirical studies as antihumanist and a suspicion that these teaching techniques stifle creativity, are not themselves located in larger theories of discourse, and might actually be demeaning to students, with exercises, far removed from actual writing situations, that boil down to “mere servile copying.” More bad news is that by the mid-1980s “[t]he result of all these lines of criticism of syntactic methods was that they were stopped almost dead in their tracks as a research program and ceased being a popular teaching project just a little later.” The good news, however, is that Connors concludes, “It really does seem that the current perception that somehow sentence rhetorics ‘don’t work’ exists as a massive piece of wish fulfillment.” As Connors explains (more good news!) in a sentence that is as carefully suspensive as his earlier sentence was balanced: “In other words, if people believe that research has shown that sentence rhetorics don’t work, their belief exists not because the record bears it out but because it is what people want to believe.”
The 5 word phrase you ask about, "English studies of empirical studies", is hard to parse when taken out of context, as you took it in the title of your question. The context "a larger suspicion in English studies of empirical studies as antihumanist" in which it occurs is clearer. It means, roughly, "a larger suspicion within English departments that empirical studies are nerdy". Here "antihumanist" means the opposite of whatever English departments most prize. More particularly, English (as an academic discipline) is conventionally grouped with the "humanities" as opposed to the "sciences", (and maybe the "arts") and "empirical studies" here are considered (by this English professor) to be distastefully scientific.
A larger question for you: do you really think this book will teach you how to write better? Judging by the number of questions you post, it seems to be giving you a lot of trouble.