# Distinguish the difference between ratios, proportions, and rates.

Measures of frequency are used to describe disease occurrence. There are four types of measures: count, ratio, proportion, and rate. Count refers to the number of cases of a disease. Proportion compares a part to a whole and may be expressed as a percentage and rate compares the frequency of a disease to the population at risk for a specific period. A rate that you are probably familiar with is the infant mortality rate. It is the number of infant deaths for every 1,000 live births. The infant mortality rate is important because it is a strong indicator of the overall health of a society (Center for Disease Control [CDC], 2020, September 10).

References

Center for Disease Control. (2020, September 10). Infant mortality. https://www.cdc.gov/reproductivehealth/maternalinfanthealth/infantmortality.htm(new tab)

Upon successful completion of this discussion, you will be able to:

• Describe the measures of frequency used in epidemiology.
• Distinguish the difference between ratios, proportions, and rates.

## Instructions

1. Review the rubric to make sure you understand the criteria for earning your grade.
2. Review from your textbook Chapter 5.
3. Review the Chapter 5 PowerPoint(PowerPoint presentation) file.