Imputes missing data in a categorical variable using polytomous regression
mice.impute.polyreg(y, ry, x, wy = NULL, nnet.maxit = 100,
nnet.trace = FALSE, nnet.MaxNWts = 1500, ...)Vector to be imputed
Logical vector of length length(y) indicating the
the subset y[ry] of elements in y to which the imputation
model is fitted. The ry generally distinguishes the observed
(TRUE) and missing values (FALSE) in y.
Numeric design matrix with length(y) rows with predictors for
y. Matrix x may have no missing values.
Logical vector of length length(y). A TRUE value
indicates locations in y for which imputations are created.
Tuning parameter for nnet().
Tuning parameter for nnet().
Tuning parameter for nnet().
Other named arguments.
Vector with imputed data, same type as y, and of length
sum(wy)
The function mice.impute.polyreg() imputes categorical response
variables by the Bayesian polytomous regression model. See J.P.L. Brand
(1999), Chapter 4, Appendix B.
By default, unordered factors with more than two levels are imputed by
mice.impute.polyreg().
The method consists of the following steps:
Fit categorical response as a multinomial model
Compute predicted categories
Add appropriate noise to predictions
The algorithm of mice.impute.polyreg uses the function
multinom() from the nnet package.
In order to avoid bias due to perfect prediction, the algorithm augment the data according to the method of White, Daniel and Royston (2010).
Van Buuren, S., Groothuis-Oudshoorn, K. (2011). mice: Multivariate
Imputation by Chained Equations in R. Journal of Statistical
Software, 45(3), 1-67. http://www.jstatsoft.org/v45/i03/
Brand, J.P.L. (1999) Development, implementation and evaluation of multiple imputation strategies for the statistical analysis of incomplete data sets. Dissertation. Rotterdam: Erasmus University.
White, I.R., Daniel, R. Royston, P. (2010). Avoiding bias due to perfect prediction in multiple imputation of incomplete categorical variables. Computational Statistics and Data Analysis, 54, 2267-2275.
Venables, W.N. & Ripley, B.D. (2002). Modern applied statistics with S-Plus (4th ed). Springer, Berlin.
Other univariate imputation functions: mice.impute.cart,
mice.impute.lda,
mice.impute.logreg.boot,
mice.impute.logreg,
mice.impute.mean,
mice.impute.midastouch,
mice.impute.norm.boot,
mice.impute.norm.nob,
mice.impute.norm.predict,
mice.impute.norm,
mice.impute.pmm,
mice.impute.polr,
mice.impute.quadratic,
mice.impute.rf,
mice.impute.ri