Biostatistics: Crude Rates and Standardized Rates, Ratios, and Estimation of Trends 1. Crude Rates Definition Formula Crude Rate=Number of Events in a Population during a Time PeriodTotal Population×100,000\text{Crude Rate} = \frac{\text{Number of Events in a Population during a Time Period}}{\text{Total Population}} \times 100,000Crude Rate=Total PopulationNumber of Events in a Population during a Time Period×100,000 Example Advantages Disadvantages 2. Standardized Rates Definition Methods of Standardization Advantages Disadvantages 3. Ratios Definition Common Ratios Uses 4. Estimation of Trends Definition Methods Uses Applications in Public Health Key Points to Remember Aspect Crude Rates Standardized Rates