For SEO (both ranking & backlink purposes), I can show you examples of long form pieces doing well and examples of breaking up the content doing well.
Publishers like to break up pieces for pageview purposes (for example, those annoying slideshows that cause you to view 30 different pages and load ads 30 different times). If you aren't a publisher attempting to inflate pageviews, then the question is if you are after links, or traffic? If getting links are most important, then creating a single comprehensive long-form piece that people see as a resource might be best.
If organic search traffic is the goal, then I would recommend looking at your piece and determining if it is covering several distinct topics. If it is, then those topics are likely diluting the overall meaning of the piece to search engines, thereby reducing the likelihood that it would rank at all. On the flip side, if the sections can't stand alone as their own pages (especially for matching searcher intent), then you'd be better off keeping them as one piece.
Here's a simplified example:
How to Choose the Right Bicycle
Types of Bikes
Right Bike for Your Height
This could make a nice, comprehensive piece and might rank for "how to choose the right bicycle" however, the meaning could be diluted by the various sections.
If, instead, you broke out those individual sections into their own articles that could stand alone, but still cross-link to each other and are a part of this sequence of related content, then you might gain more traffic.
We have tested different length of the posts:1600-1800 words is the optimal length of a blog purely from an SEO perspective.This type of blog is hard to produce (on average, it takes 10-12 hours to write and edit as it also requires quality/unique content and references to credible supporting materials).
Therefore, in addition to 1 main long form post, you can also create a number of related posts (600-800) going deeper into specific parts of the topic without duplication. SEO improves significantly if you a) have a content strategy that is focused on depth not breadth of content and b) create a plan to repurpose your content and c) maximize your content via social sharing
Not answering your question directly, but I listened to a podcast with the CEO of Text.io, Kieran Snyder, that does text analyzes to improve job descriptions to attract better candidates, and they did a study with Kickstarter campaigns -- unrelated to hiring/JDs -- and found out that campaigns with longer texts were more successful than campaigns with shorter texts.
This is a correlation, they haven't proved causation, but it does makes you think that a comprehensive explanation on a single page might yield better conversion, even if people don't read it (ignoring SEO here, which I actually don't know the answer to).If someone has A/B tested this I'd love to know the results.