Documentation: one long page or several short pages

We're working on the design and organization of our documentation. The current structure is something like this:

• General info on topic
  • specialized sub-topic 1
  • specialized sub-topic 2
  • specialized sub-topic 3

(Note that "General info on topic" is itself nested under a much broader topic, so that "specialized sub-topic 1" is at the 3rd level, but I can't make the markdown represent that.)

The question is whether to keep this multi-page, nested format or combine all the content into one page with a Table of Contents at the top.

My previous experience as a journalist tells me that readership drops off the longer your content piece (hence our current organization). But I recognize that things may have changed a little from the ink-on-paper paradigm. I've tried to do some research, but most of what I'm finding seems to be in a much more commercial context ("don't put all your ads above the fold" and so on) or about infini-scroll. This question touches on the subject, but doesn't quite address what I need.

So: long multi-topic docs pages, or short topic-specific pages? I'm hoping for studies & statistics, but will settle for anecdotal experience.