#### Expected Points

Expected points are an estimate of points per place based on down, distance and line of scrimmage, using
past results from collected historical data.

Points given for offence and defence are offensive/defensive plays and plays negated by pentalty. Offensive
and defensive breakdowns (run/pass) may not add up due to penalties or other plays (eg: bad snap or kneel).

Special teams plays are all kicking plays. Bad snap and kneel downs from punt formations are counted as
general offence or defence.

Last play of half is considered to be worth 0 points unless it is a scoring play.

Turnovers are considered to be the lost value of the pre-play expectation and the negative value of the
opponent's next play expectation

#### Simple Rating System (SRS)

In simple terms, the formula for SRS is a team's average point margin, plus the average of their opponents'
ratings. It was implemented here according to the information helpfully provided by Doug Drinen of
Pro-Football-Reference
here.

To quote Mr. Drinen's article:

So every team's rating is their average point margin, adjusted up or down depending on the strength of their
opponents. Thus an average team would have a rating of zero. Suppose a team plays a schedule that is,
overall, exactly average. Then the sum of the terms in parentheses would be zero and the team's rating would
be its average point margin. If a team played a tougher-than-average schedule, the sum of the terms in
parentheses would be positive and so a team's rating would be bigger than its average point margin.