deductiveLevels {deducorrect}

Derive imputation values for categorical data

Description

Deduce imputation values for categorical data. By substituting all known values and interatively eliminating the unknowns from the set of edits, unique imputation values are derived where possible.

Usage

deductiveLevels(E, x, adapt = rep(FALSE, length(x)),
  checkFeasibility = TRUE)

Arguments

E

editarray

x

a named character vector

adapt

boolean vector indicating which variables may be adapted.

checkFeasibility

Test wether the assumed-correct values (observed and not designated by adapt) can lead to a consistent record.

Details

Imputation values are derived for missing variables (NA) and for variables indicated by 'adapt'.

Value

A named vector with imputation values for x

References

T. De Waal, J. Pannekoek and S. Scholtus (2011) Handbook of statistical data editing Chpt 9.2.1 - 9.2.2

Examples

# a simple example. We know the subject is pregnant. What is the gender?
E <- editarray(c(
    "gender \%in\% c('male','female')",
    "pregnant \%in\% c(TRUE,FALSE)",
    "if ( gender=='male') !pregnant"))
# a record with unknown gender
x <- c(gender=NA,pregnant=TRUE)

# find imputations
(s <- deductiveLevels(E,x))

# imputation can be done as follows:
x[names(s)] <- s



# Here's an example from De Waal et al (2011) (ex. 9.3)
E <- editarray(c(
    "x1 \%in\% letters[1:4]",
    "x2 \%in\% letters[1:3]",
    "x3 \%in\% letters[1:3]",
    "x4 \%in\% letters[1:2]",
    "if (x2 == 'c'  & x3 != 'c' & x4 == 'a' ) FALSE",
    "if (x2 != 'a'  & x4 == 'b') FALSE",
    "if (x1 != 'c'  & x2 != 'b' & x3 != 'a') FALSE",
    "if (x1 == 'c'  & x3 != 'a' & x4 == 'a' ) FALSE"
))

x <- c(x1='c',x2='b',x3=NA,x4=NA)
(s <- deductiveLevels(E,x))

x[names(s)] <- s


# another example, partial imputation
y <- c(x1=NA,x2=NA,x3=NA,x4='b')
(s <- deductiveLevels(E,y))

y[names(s)] <- s