# Calculates effective number of parties for incomplete data

### Description

This function calculates the effective number of parties with incomplete data, as introduced by Taagepera (1997). It can be used to estimate the effective number of groups in a population.

### Usage

1 | ```
neffIncomp(x)
``` |

### Arguments

`x` |
Population vector, the residual category (‘other’) needs to be last |

### Details

This function calculates the number of effective parties if data are incomplete, i.e. if there is a residual category (‘other’). This function can be used to enumerate the effective number of parties, but also the effective number of groups in a population or representative body.

Note that the residual category is assumed to be the last item in the population vector. The best estimate (`Neff`

) may be incorrect if certain small parties or groups are listed for historical (or other) importance. In this case, the error range would be underestimated.

### Value

Returns a list: `Neff`

gives the best estimate (in the absence of other information), `simple`

does not square the residual category, `low`

treats the residual category a group on its own, `least`

assumes the groups in the residual category to be at least as big as the smallest group given, and `high`

excludes the residual category.

### Author(s)

Didier Ruedin

### References

Taagepera, R. (1997) Effective Number of Parties for Incoplete Data. Electoral Studies 16(2): 145-51.

### See Also

`neff`