# Model performance statistics.

### Description

Function estimates several statistics comparing modelled and reference (measured) values.

### Usage

1 2 3 |

### Arguments

`calculated` |
Vector of length n of the calculated (modelled) values. |

`measured` |
Vector of length n of the reference (measured) values. |

`stat` |
Statistics which are going to be calculated. By default all possible. |

`minlength` |
Minimum number of non-NA data pairs. If below this value, the NA's are produced. |

### Details

The two input vectors can include NA's. Only non-NA calculated-mesured pairs are used. See 'na.omit' for details.

### Value

List of 13 statistics:

`N` |
number of observations |

`person` |
Pearson's Correlation Coefficient |

`MBE` |
Mean (Bias) Error |

`RMBE` |
Relative Mean (Bias) Error |

`MAE` |
Mean Absolute Error |

`RMAE` |
Relative Mean Absolute Error |

`RMSE` |
Root Mean Square Error |

`RRMSE` |
Relative Root Mean Square Error |

`R2` |
Coefficient of determination from linear model |

`slope` |
Slope from linear model |

`intercept` |
Intercept from linear model |

`EF` |
Modelling Efficiency |

`SD` |
Standard deviation of differences |

`CRM` |
Coefficient of Residual Mass |

`MPE` |
Mean Percentage Error |

`AC` |
Agreement Coefficient |

`ACu` |
Unsystematic Agreement Coefficient |

`ACs` |
Systematic Agreement Coefficient |

### Author(s)

Jedrzej S. Bojanowski

### References

Bellocchi, G., Acutis, M., Fila, G., Donatelli, M., 2002. An indicator of solar radiation model performance based on a fuzzy expert system. Agronomy Journal 94, 1222-1233.

Ji, L., Gallo, K., 2006. An Agreement Coefficient for image comparison. Photogrammetric Engineering & Remote Sensing 72(7), 823-833.

### Examples

1 2 3 4 5 6 7 8 9 10 11 | ```
data(Metdata)
B <- 0.11
tmax <- Metdata$meteo$TEMP_MAX
tmin <- Metdata$meteo$TEMP_MIN
days <- Metdata$meteo$DAY
lat <- Metdata$LATITUDE
solrad_measured <- Metdata$meteo$RAD_MEA
solrad_BC <- bc(days, lat, extraT=NULL, BCb=B, tmax, tmin, BCc=2, tal=0.76)
modeval(solrad_BC,solrad_measured)
modeval(solrad_BC,solrad_measured,stat="EF")
``` |