afc.dm {afc} | R Documentation |

## 2AFC For Dichotomous Observations And Ordinal Polychotomous Forecasts

### Description

Routine to calculate the Generalized Discrimination Score (aka Two-Alternatives Forced Choice Score 2AFC) for the situation of dichotomous observations and (ordinal) polychotomous forecasts

### Usage

```
afc.dm(obsv, fcst, mf = 3)
```

### Arguments

`obsv` |
vector with dichotomous observations (values in 0,1) |

`fcst` |
vector of same length as |

`mf` |
number of forecast categories (default = 3) |

### Details

This routine applies Eq.5 of in Mason and Weigel (2009) to calculate the 2AFC.

### Value

`p.afc` |
Value of Generalized Discrimination (2AFC) Score |

### Author(s)

Andreas Weigel, Federal Office of Meteorology and Climatology, MeteoSwiss, Zurich, Switzerland

### References

S.J. Mason and A.P. Weigel, 2009. A generic verification framework for administrative purposes. Mon. Wea. Rev., 137, 331-349

### See Also

### Examples

```
#Forecasts and observations of Nino-3.4 index
#Load set of dichotomous observations and polychotomous forecasts (4 categories)
data(cnrm.nino34.dm)
obsv = cnrm.nino34.dm$obsv
fcst = cnrm.nino34.dm$fcst
#Calculate skill score
afc.dm(obsv,fcst,4)
```

[Package

*afc*version 1.4.0 Index]