How to gauge scientific progress? Here's an explanation of the arcane terms used by the Brainers. Note that their estimations can be wildly inaccurate.
Unknown: less than 33% of the base cost has been researched;
Poor: over 2 weeks total at the current number of assigned Brainers;
Average: more than a week total research time;
Good: 4-7 days;
Excellent: 3 days or less.