SAS, SPSS, and Stata share a simply concept of “labelled” vectors, which are similar to factors but a little more general. The
labelled() class provides a natural representaion in R.
Both SAS and Stata supported tagged missing values, where a missing value can have multiple “types”, given by an letter from A through Z.
tagged_na() provides a convenient way of representing these types of missing values in R by taking advantage of the binary representation of
There are a number of SPSS/SAS/Stata features that have no direct equivalent in R. Haven preserves them so you can choose what do with them. To simply eliminate them, use one of the zap functions.