Coefficient of efficiency (CE1)

$\text{CE}1=1-\frac{{{\displaystyle \sum }}_{i=1}^n{\left(x_{iexp}-x_{ipred}\right)}^2}{{{\displaystyle \sum }}_{i=1}^n{\left(x_{iexp}-\overline{X_e}\right)}^2}$

[81]

Coefficient of efficiency (CE2)

$\text{CE}2=1-\frac{{{\displaystyle \sum }}_{i=1}^n{\left(x_{iexp}-x_{ipred}\right)}^2}{{{\displaystyle \sum }}_{i=1}^n{\left(x_{iexp}-\overline{X_p}\right)}^2}$

[79]

Nash Coefficient of efficiency (NSE)

$\text{NSE}=1-\frac{{{\displaystyle \sum }}_{i=1}^n{\left(x_{ipred}-x_{iexp}\right)}^2}{{{\displaystyle \sum }}_{i=1}^n{\left(x_{iexp}-\overline{X_e}\right)}^2}$

[49] [32]

Standard Error of Prediction (SEP%)

$\text{SEP}\%=\frac{\text{RMSE}}{\overline{X_e}}\times 100$

[20] [38] [39] [52] [64]