Imputation refers to the replacement process of missing data, and this is the case of entries in the
Epigraphic Database Heidelberg and related datasets.
In this context, the missing data for imputation are the endpoints of the timespan of existence of epigraphs or inscriptions
represented by variables TAQ and TPQ (cf. prex) as "not_before" and "not_after" in the EDH dataset
with cases of censoring with one limit of the timespan known.
To perform imputation on subsets of missing dating data in the EDH dataset,
function edhwpd serves to organize records per Roman province and dates
by simple match similarity of different attribute variables specified in vars.
Such organisation is in the form of a dataframe or a list of dataframes depending on the province characteristics, and
a restricted multiply-imputed data subsets takes place on this outcome, and where collapse is for
collapsing lists of dataframes.
When dating data is complete missing, rpd provides the average date, min TAQ, max TPQ, and the average length timespan
for each Roman province that applies for a multiple imputation.