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# Jest

Validate output by making calculations by hand

**Example Calculations**

***.sharedJest**

Estimating the fraction of sequences that belong to shared OTUs.

Just as the Chao1 richness estimator is a function of the number of OTUs observed once or twice in a sample (6), the estimators of the fraction of sequences in shared OTUs is a function of the number of shared OTUs that are observed at least once or twice in the community being analyzed (8, 7). <math>{S_{Jest}}</math> is essentially a form of the equation for <math>J_{abund}</math> that is not corrected for the presence of unsampled OTUs.

<math>S_{Jest} = \frac{S_{A,B Chao}}{S1_{chao} + S2_{chao} - S_{A,B Chao}}</math>,

where,

<math>S_{A,B Chao}</math> = estimated number of OTUs shared between A and B using the <math>S_{A,B Chao}</math> estimator.

<math>S1_{chao}</math> = number of OTUs estimated in A using the Chao estimator.

<math>S2_{chao}</math> = number of OTUs estimated in B using the Chao estimator.

At distance 0.03, the <math>S_{Jest}</math> value is 0.705297.