Table 1

Evaluation measures for test data

-50 %

-25 %

Equal

+25 %

+50 %


tp

750

750

750

750

750

fn

250

250

250

250

250

tn

375

563

750

938

1125

fp

125

187

250

312

375

sensitivity

0.75

0.75

0.75

0.75

0.75

specificity

0.75

0.75

0.75

0.75

0.75

PPV

0.86

0.80

0.75

0.71

0.67

NPV

0.60

0.69

0.75

0.79

0.82

accuracy

0.75

0.75

0.75

0.75

0.75

MCC

0.48

0.50

0.50

0.50

0.49


Example of a situation when both positive and negative cases have the same rate of correct predictions (75 %) and when the amount of negative cases is either equal or 25 or 50 % lower or higher than that for positive cases.

Vihinen BMC Genomics 2012 13(Suppl 4):S2   doi:10.1186/1471-2164-13-S4-S2

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