Folks are pretty close on the money for Paizo adventures.
We generally assume about 900 words for a full page of text. Stat blocks and illustrations reduce this number, obviously.
For a 32 page module, we ask our authors to provide 20,000 words.
For a Pathifnder adventure path installment, we ask the authors to provide 35,000 words. The remaining 30,000 or so words in a Pathfinder AP volume consists of new monsters, support articles, fiction, and the like.
Some more fun statistics we assume:
- A half-page illustration counts as about 500 words.
- A full-body illustration of an NPC counts as about 400 words.
- A spot illustration (such as an item or an NPC's head) counts as 150 words.
- An average encounter in an adventure is about 500 words.
- The opening of an adventure, including the Adventure Background and Adventure Synopsis should try to be no more than 5% of the total adventure's length (this works out to about a page for a module, and about two pages for an Adventure Path installment); less words is always better for the background/summary.
- A 2-page Pathfinder AP style new monster is 1,400 words, counting the stat block.
- A 1-page, hardcover Bestiary style monster entry is about 550 words (including stat block).
- High level adventures tend to take up more room on an encounter-by-encounter basis, partially due to larger stat blocks, but mostly due to the fact that you have to account for a much wider range of possible PC actions and abilities.
- 2,000 words of workable writing progress is considered an average day's work.
- 5,000 words of workable writing progress in a day is considered phenomenal.