I just got my COR certification results back and I passed with an 84%. Honestly didn't think I'd get there after failing twice, so I wanted to share what finally clicked for me in case anyone else is grinding through this thing right now.
The first two times I studied almost exclusively from the IHSA materials and figured that was enough. It wasn't. What changed my third attempt was using a decent COR practice test to figure out where my actual gaps were — I kept bombing questions around the hazard assessment documentation requirements and emergency response planning sections, which I never would have identified just by re-reading the manual. Once I knew my weak spots, I built a targeted study guide around those topics instead of going cover-to-cover again.
Total study time was probably 35-40 hours spread over six weeks this time versus cramming 20 hours in two weeks before the previous attempts. The pacing made a huge difference. If you're just starting out, my biggest COR exam tip is don't underestimate the health and safety management system questions — they show up constantly and the wording can be tricky.