Enter the prevalence in the test group and the prevalence in the control group into the Prevalence Ratio Calculator. The calculator will evaluate and display the Prevalence Ratio. 

Prevalence Ratio Formula

The following formula is used to calculate the Prevalence Ratio. 

PR = PT / PC
  • Where PR is the Prevalence Ratio ( )
  • PT is the prevalence in test group 
  • PC is the prevalence in control group 

To calculate the prevalence ratio, divide the prevalence in the test group by the prevalence in the control group.

How to Calculate Prevalence Ratio?

The following example problems outline how to calculate Prevalence Ratio.

Example Problem #1:

  1. First, determine the prevalence in test group.
    • The prevalence in test group is given as: .75.
  2. Next, determine the prevalence in control group.
    • The prevalence in control group is provided as: .90.
  3. Finally, calculate the Prevalence Ratio using the equation above: 

PR = PT / PC

The values given above are inserted into the equation below and the solution is calculated:

PR = .75 / .90 = .833

Example Problem #2: 

For this problem, the variables required are provided below:

prevalence in test group = .60

prevalence in control group = .50

Test your knowledge using the equation and check your answer with the calculator above.

PR = PT / PC = ?