Table 2 Generally recommended values for the validation parameters for a built model

R²

Coefficient of determination

≥0.6

P_(95%)

Confidence interval at 95% confidence level

<0.05

\( {Q}_{cv}^2 \)

Cross validation coefficient

≥0.5

R² -\( {Q}_{cv}^2 \)

Difference between R² and \( {Q}_{cv}^2 \)

<0.3

N_{(ext & test set)}

Minimum number of external test set

≥5

\( c{R}_p^2 \)

Coefficient of determination for Y-randomization

≥0.5