Build columns from the expected dropback model will return NA on data prior to 2006
since that was before NFL started marking scrambles. Must be run on a dataframe that has already had
clean_pbp run on it, such as data from the data repository or
build_nflfastR_pbp or built using the database function update_db.
add_xpass(pbp, ...)is a Data frame of play-by-play data scraped using fast_scraper.
Additional arguments passed to a message function (for internal use).
The input Data Frame of the parameter pbp with the following columns
added:
Probability of dropback scaled from 0 to 1.
Dropback percent over expected on a given play scaled from 0 to 100.