Yea, i think that's correct. documentation is just another product, no different than other software.
so basically you can start asking with very common user reasearch questions such as:
* who would use our documentation?
* what would our user need the most from our documentation?
"I wonder if there is a good way to measure documentation quality"
I would start with a checklist:
- is it complete and consistent
- is there a description to every important piece
- working examples
... and if this is complete, you can measure all you want, but I would start with the basics.
I wonder if there is a good way to measure documentation quality...I suspect such measures will require techniques borrowed from user experience research.