Discriminatory Power Calculator
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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 |
The Discriminatory Power (D), as shown by Hunter can be expressed by the
formula of Simpson�s index of diversity, which reads:
 Where D is the index of discriminatory power, N the number of unrelated strains tested, S the number of different types, and xj the number of strains belonging to the jth type, assuming that strains will be classified into mutually exclusive categories. Thus, a D value of 1.0 would indicate that a typing method was able to distinguish each member of a strain population from all other members of that population. Conversely, an index of 0.0 would indicate that all members of a strain population were of an identical type. An index of 0.50 would mean that if one strain was chosen at random from a strain population, then there would be a 50% probability that the next strain chosen at random would be indistinguishable from the first.
References:
Hunter PR and Gaston MA. Numerical index of the discriminatory ability of typing systems: an application of Simpson�s index of diversity. J Clin Microbiol. 1988 November; 26(11): 2465�2466. PubMed
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