Discriminatory Power Calculator

The Discriminatory Power (D) is the average probability that the typing system will assign a different type to two unrelated strains randomly sampled in the microbial population of a given taxon.

This tool has been created to help calculate this parameter, and source code is available at biophp.org

Add number of samples assigned to each type separated by comma:

Number of unrelated strains:100
Number of types:4
Discriminatory power:0.7071

Example: a novel typing system was used to type 100 randomly sampled E. coli strains. Four types were obtained, and to each type the following number of strains was assigned:

Type A: 40 strains
Type B: 30 strains
Type C: 20 strains
Type D: 10 strains

With this data, discriminatory power was calculated and its value was 0.7071