data_followup: Build follow-up data frame
Description
Build follow-up data frame
Usage
data_followup(data_exposures)
Value
A data frame in which each row corresponds to a sportsperson and
his/her first date (t0) and last date (tf) observed.
Arguments
- data_exposures
Exposure data frame with standardized column names, in
the same fashion that prepare_exp() returns.