R: Finds an imputed value from matches in the predictive metric...

.pmm.match {mice} | R Documentation

## Finds an imputed value from matches in the predictive metric (deprecated)

### Description

This function finds matches among the observed data in the predictive mean metric. It selects the `donors` closest matches, randomly samples one of the donors, and returns the observed value of the match.

### Usage

    .pmm.match(z, yhat = yhat, y = y, donors = 5, ...)

### Arguments

`z` | A scalar containing the predicted value for the current case to be imputed.
`yhat` | A vector containing the predicted values for all cases with an observed outcome.
`y` | A vector of `length(yhat)` elements containing the observed outcome
`donors` | The size of the donor pool among which a draw is made. The default is `donors = 5`. Setting `donors = 1` always selects the closest match. Values between 3 and 10 provide the best results. Note: This setting was changed from 3 to 5 in version 2.19, based on simulation work by Tim Morris (UCL).
`...` | Other parameters (not used).

### Details

This function is included for backward compatibility. It was used up to `mice 2.21`. The current `mice.impute.pmm()` function calls the faster `C` function `matcher` instead of `.pmm.match()`.

### Value

A scalar containing the observed value of the selected donor.

### Author(s)

Stef van Buuren

### References

Schenker N \& Taylor JMG (1996) Partially parametric techniques for multiple imputation. Computational Statistics and Data Analysis, 22, 425-446.

Little RJA (1988) Missing-data adjustments in large surveys (with discussion). Journal of Business Economics and Statistics, 6, 287-301.

[Package mice version 3.12.0 Index]