Social & Preventive Medicine Bias is unlikely to invalidate coho studies used to assess risk risk of exposure because- A Data collection is prospective B Large number of subjects is usually included C Exposure is usually determined prior to disease occurrence D Actual relative risk can be determined 💡 Explanation Bias is unlikely to invalidate coho studies used to assess risk risk of exposure because- ✓ Correct Answer: C. Exposure is usually determined prior to disease occurrence