NFL — additional Python functions — Models and calculators: calculate_epa

calculate_epa

calculate_epa(df: 'pl.DataFrame') -> 'pl.DataFrame'

Derive expected points added (EPA) from pre-scored EP point estimates.

This is the derivation half of NFLPlayProcess.__process_epa lifted into a shared, model-free function so the same nflfastR-faithful EPA logic can be reused by the streaming enrich_nfl_pbp pipeline and by process_epa` itself. It performs no model inference — the caller must already have scored the per-play EP point estimates.

Derivation rules (mirror nflfastR / the original process_epa`):

• Scoring overlays rewrite EP_end to the realized point value (offense TD +7 / +6.92 / 2pt variants, made FG +3, defensive scores, extra points, etc.) using the same type.text / text classification as process_epa`.
• Turnovers (end_change_vec / downs_turnover), kickoff turnovers and recovered onside kicks flip EP_end to the opponent's perspective (EP_end * -1).
• lag_EP_end is the previous play's EP_end; EP_between flips its sign on a prior-play possession change.
• Kickoffs use EP_start_touchback as EP_start.
• EPA = EP_end - EP_start normally; -EP_start on a non-scoring end-of-half play; 0 on a timeout; EP_end - EP_start + EP_between on a (non-kickoff, non-Penalty) penalty-in-text play.

Every shift is grouped .over("game_id") so a concatenated multi-game frame never leaks EP across game boundaries — this differs from process_epa` (which runs one game per instance and therefore needs no grouping).

Parameters

Parameter	Type	Default	Description
df	DataFrame		Play-by-play DataFrame that already carries the EP point estimates under the ESPN-internal names EP_start, EP_end and EP_start_touchback (e.g. as produced by the EP-scoring half of process_epa), plus the play-classification / flag columns: game_id, type.text, text, change_of_pos_team, downs_turnover, kickoff_onside, scoring_play, end_of_halfandpenalty_in_text. See EPA_REQUIRED_COLUMNS. This function does not score EP itself — score it first via the EP feature pipeline (the EP_* triple is the ESPN-internal naming, distinct from calculate_expected_points's lowercase ep).

Returns

The input frame with the EPA derivation applied. EP_start is rewritten to 0.92 for scoring-attempt play types (Extra Point Good, Extra Point Missed, Two-Point Conversion Good, Two-Point Conversion Missed, Two Point Pass, Two Point Rush, Blocked PAT, Defensive 2pt Conversion) before any other overlays fire. EP_start / EP_end are then rewritten in place (overlays, sign flips, touchback), EP_between, lag_EP_end and lag_change_of_pos_team are added, EPA is added, and lowercase nflverse aliases ep (= EP_end), epa (= EPA), ep_start (= EP_start) and ep_end (= EP_end) are added for downstream contract parity.

col_name	type	description
game_play_number	integer
id	integer	ID of the player in the 'name' column.
sequenceNumber	integer
text	character
awayScore	integer
homeScore	integer
scoringPlay	logical	ESPN flag marking the play as a scoring play.
priority	logical
modified	character
wallclock	character
teamParticipants	integer	Raw ESPN team-level participants payload carried through from the plays feed (stringified).
isPenalty	logical	ESPN's per-play flag that a penalty occurred on the play.
statYardage	integer	Yardage ESPN credits to the play for statistical purposes.
isTurnover	logical	ESPN's per-play turnover flag as shipped in the plays feed (broader than the giveaway-based is_turnover derivation).
type.id	character	ESPN's numeric identifier for the play type.
type.text	character	ESPN's text label for the play type.
period.number	integer	Period (quarter) number in which the play occurred.
clock.displayValue	character	Game clock at the play, as the displayed mm:ss string.
start.down	integer	ESPN's down value for the play state at the start of the play.
start.distance	integer	ESPN's distance value for the play state at the start of the play.
start.yardLine	integer	ESPN's yardLine value for the play state at the start of the play.
start.yardsToEndzone	integer	ESPN's yardsToEndzone value for the play state at the start of the play.
start.team.id	integer	ESPN's team.id value for the play state at the start of the play.
end.down	integer	ESPN's down value for the play state at the end of the play.
end.distance	integer	ESPN's distance value for the play state at the end of the play.
end.yardLine	integer	ESPN's yardLine value for the play state at the end of the play.
end.yardsToEndzone	integer	ESPN's yardsToEndzone value for the play state at the end of the play.
end.team.id	integer	ESPN's team.id value for the play state at the end of the play.
type.abbreviation	character	ESPN's abbreviation for the play type.
start.downDistanceText	character	ESPN's downDistanceText value for the play state at the start of the play.
start.shortDownDistanceText	character	ESPN's shortDownDistanceText value for the play state at the start of the play.
start.possessionText	character	ESPN's possessionText value for the play state at the start of the play.
end.downDistanceText	character	ESPN's downDistanceText value for the play state at the end of the play.
end.shortDownDistanceText	character	ESPN's shortDownDistanceText value for the play state at the end of the play.
end.possessionText	character	ESPN's possessionText value for the play state at the end of the play.
scoringType.name	character	ESPN's name for the scoring type (e.g. touchdown, field goal).
scoringType.displayName	character	ESPN's display label for the scoring type.
scoringType.abbreviation	character	ESPN's abbreviation for the scoring type.
pointAfterAttempt.id	double	ESPN identifier for the point-after attempt type on the scoring play.
pointAfterAttempt.text	character	ESPN description of the point-after attempt and its result.
pointAfterAttempt.abbreviation	character	ESPN abbreviation of the point-after attempt type; drives the extra-point / two-point result derivation.
pointAfterAttempt.value	double	Points ESPN credits for the point-after attempt (1.0 made extra point, 2.0 made two-point try).
drive.id	character	ESPN's id field for the drive containing this play.
drive.displayResult	character	ESPN's displayResult field for the drive containing this play.
drive.isScore	logical	ESPN's isScore field for the drive containing this play.
drive.team.shortDisplayName	character	ESPN's team.shortDisplayName field for the drive containing this play.
drive.team.displayName	character	ESPN's team.displayName field for the drive containing this play.
drive.team.name	character	ESPN's team.name field for the drive containing this play.
drive.team.abbreviation	character	ESPN's team.abbreviation field for the drive containing this play.
drive.yards	integer	ESPN's yards field for the drive containing this play.
drive.offensivePlays	integer	ESPN's offensivePlays field for the drive containing this play.
drive.result	character	ESPN's result field for the drive containing this play.
drive.description	character	ESPN's description field for the drive containing this play.
drive.shortDisplayResult	character	ESPN's shortDisplayResult field for the drive containing this play.
drive.timeElapsed.displayValue	character	ESPN's timeElapsed.displayValue field for the drive containing this play.
drive.start.period.number	integer	ESPN's start.period.number field for the drive containing this play.
drive.start.period.type	character	ESPN's start.period.type field for the drive containing this play.
drive.start.yardLine	integer	ESPN's start.yardLine field for the drive containing this play.
drive.start.clock.displayValue	character	ESPN's start.clock.displayValue field for the drive containing this play.
drive.start.text	character	ESPN's start.text field for the drive containing this play.
drive.end.period.number	integer	ESPN's end.period.number field for the drive containing this play.
drive.end.period.type	character	ESPN's end.period.type field for the drive containing this play.
drive.end.yardLine	integer	ESPN's end.yardLine field for the drive containing this play.
drive.end.clock.displayValue	character	ESPN's end.clock.displayValue field for the drive containing this play.
game_id	integer	Ten digit identifier for NFL game.
season	integer	4 digit number indicating to which season(s) the specified timeframe belongs to.
seasonType	integer	ESPN season type for the game (2 = regular season, 3 = postseason).
week	integer	Season week.
status_type_completed	logical
homeTeamId	integer	ESPN's home-team Id for the game, stamped on every play.
awayTeamId	integer	ESPN's away-team Id for the game, stamped on every play.
homeTeamName	character	ESPN's home-team Name for the game, stamped on every play.
awayTeamName	character	ESPN's away-team Name for the game, stamped on every play.
homeTeamMascot	character	ESPN's home-team Mascot for the game, stamped on every play.
awayTeamMascot	character	ESPN's away-team Mascot for the game, stamped on every play.
homeTeamAbbrev	character	ESPN's home-team Abbrev for the game, stamped on every play.
awayTeamAbbrev	character	ESPN's away-team Abbrev for the game, stamped on every play.
homeTeamNameAlt	character	ESPN's home-team NameAlt for the game, stamped on every play.
awayTeamNameAlt	character	ESPN's away-team NameAlt for the game, stamped on every play.
gameSpread	double	Point spread used as an input to the win-probability model.
homeFavorite	logical	True when the home team was favoured by the spread.
gameSpreadAvailable	logical	True when a spread was available for the game.
overUnder	double	Over/under total used as a model input.
roof	character	One of 'dome', 'outdoors', 'closed', 'open' indicating indicating the roof status of the stadium the game was played in. (Source: Pro-Football-Reference)
homeTeamSpread	double	ESPN's home-team Spread for the game, stamped on every play.
clock.minutes	integer	Minutes remaining on the game clock at the play.
clock.seconds	integer	Seconds component of the game clock at the play.
half	integer
lag_half	integer	Value of half on the previous play, used for sequence-aware derivations.
lead_half	integer	Value of half on the next play, used for sequence-aware derivations.
start.TimeSecsRem	integer	Seconds remaining in the half from ESPN's clock stamp for this play, which is the end-of-play time in 2005 and 2007+ (the snap time in 2004 and most of 2006); tops out at 1800.
start.adj_TimeSecsRem	integer	ESPN's adj_TimeSecsRem value for the play state at the start of the play.
orig_play_type	character
lead_text	character	Value of text on the next play, used for sequence-aware derivations.
lead_start_team	character	Value of start_team on the next play, used for sequence-aware derivations.
lead_start_yardsToEndzone	integer	Value of start_yardsToEndzone on the next play, used for sequence-aware derivations.
lead_start_down	integer	Value of start_down on the next play, used for sequence-aware derivations.
lead_start_distance	integer	Value of start_distance on the next play, used for sequence-aware derivations.
lead_scoringPlay	logical	Value of scoringPlay on the next play, used for sequence-aware derivations.
text_dupe	logical	Always False in the emitted frame -- the duplicate-row filter it gates runs before the column is returned, so it marks nothing and is retained only for schema stability.
start.pos_team.id	integer	ESPN's pos_team.id value for the play state at the start of the play.
start.def_pos_team.id	integer	ESPN's def_pos_team.id value for the play state at the start of the play.
end.def_pos_team.id	integer	ESPN's def_pos_team.id value for the play state at the end of the play.
end.pos_team.id	integer	ESPN's pos_team.id value for the play state at the end of the play.
start.pos_team.name	character	ESPN's pos_team.name value for the play state at the start of the play.
start.def_pos_team.name	character	ESPN's def_pos_team.name value for the play state at the start of the play.
end.pos_team.name	character	ESPN's pos_team.name value for the play state at the end of the play.
end.def_pos_team.name	character	ESPN's def_pos_team.name value for the play state at the end of the play.
start.is_home	logical	ESPN's is_home value for the play state at the start of the play.
end.is_home	logical	ESPN's is_home value for the play state at the end of the play.
homeTimeoutCalled	logical	True when the home team called a timeout on the play.
awayTimeoutCalled	logical	True when the away team called a timeout on the play.
end.homeTeamTimeouts	integer	ESPN's homeTeamTimeouts value for the play state at the end of the play.
end.awayTeamTimeouts	integer	ESPN's awayTeamTimeouts value for the play state at the end of the play.
start.homeTeamTimeouts	integer	ESPN's homeTeamTimeouts value for the play state at the start of the play.
start.awayTeamTimeouts	integer	ESPN's awayTeamTimeouts value for the play state at the start of the play.
end.TimeSecsRem	integer	Seconds remaining in the half carried as this play's end state; currently the preceding row's clock stamp.
end.adj_TimeSecsRem	integer	ESPN's adj_TimeSecsRem value for the play state at the end of the play.
start.posTeamTimeouts	integer	ESPN's posTeamTimeouts value for the play state at the start of the play.
start.defPosTeamTimeouts	integer	ESPN's defPosTeamTimeouts value for the play state at the start of the play.
end.posTeamTimeouts	integer	ESPN's posTeamTimeouts value for the play state at the end of the play.
end.defPosTeamTimeouts	integer	ESPN's defPosTeamTimeouts value for the play state at the end of the play.
firstHalfKickoffTeamId	integer	ESPN id of the team that received the opening kickoff.
period	integer
start.yard	integer	ESPN's yard value for the play state at the start of the play.
end.yard	integer	ESPN's yard value for the play state at the end of the play.
lag_scoringPlay	logical	Value of scoringPlay on the previous play, used for sequence-aware derivations.
end_of_half	logical
down_1	logical	True when it is 1st down at the start of the play.
down_2	logical	True when it is 2nd down at the start of the play.
down_3	logical	True when it is 3rd down at the start of the play.
down_4	logical	True when it is 4th down at the start of the play.
down_1_end	logical	True when it is 1st down at the end of the play.
down_2_end	logical	True when it is 2nd down at the end of the play.
down_3_end	logical	True when it is 3rd down at the end of the play.
down_4_end	logical	True when it is 4th down at the end of the play.
scoring_play	logical
td_play	logical
touchdown	logical	Binary indicator for if the play resulted in a TD.
td_check	logical	Internal flag used while reconciling whether the play produced a touchdown.
safety	logical	Binary indicator for whether or not a safety occurred.
fumble_vec	logical
forced_fumble	logical	True when the defense forced a fumble on the play.
kickoff_play	logical
kickoff_tb	logical
kickoff_onside	logical
kickoff_oob	logical
kickoff_fair_catch	logical	Binary indicator for if the kickoff was caught with a fair catch.
kickoff_downed	logical	Binary indicator for if the kickoff was downed.
kick_play	logical
kickoff_safety	logical
punt	logical
punt_play	logical
punt_tb	logical
punt_oob	logical
punt_fair_catch	logical	Binary indicator for if the punt was caught with a fair catch.
punt_downed	logical	Binary indicator for if the punt was downed.
punt_safety	logical
punt_blocked	logical	Binary indicator for if the punt was blocked.
penalty_safety	logical
rush	logical	Binary indicator if the play was a rushing play.
pass	logical	Binary indicator if the play was a pass play (sacks and scrambles included).
sack_vec	logical
pos_team	integer
def_pos_team	integer
is_home	logical
lag_HA_score_diff	integer	Value of HA_score_diff on the previous play, used for sequence-aware derivations.
HA_score_diff	integer	Home score minus away score for the play.
net_HA_score_pts	integer	Net points the play added to the home-minus-away score margin.
H_score_diff	integer	Home team's score minus the away team's, from the home perspective.
A_score_diff	integer	Away team's score minus the home team's, from the away perspective.
lag_homeScore	integer	Value of homeScore on the previous play, used for sequence-aware derivations.
lag_awayScore	integer	Value of awayScore on the previous play, used for sequence-aware derivations.
start.homeScore	integer	ESPN's homeScore value for the play state at the start of the play.
start.awayScore	integer	ESPN's awayScore value for the play state at the start of the play.
end.homeScore	integer	ESPN's homeScore value for the play state at the end of the play.
end.awayScore	integer	ESPN's awayScore value for the play state at the end of the play.
pos_team_score	integer
def_pos_team_score	integer
start.pos_team_score	integer	ESPN's pos_team_score value for the play state at the start of the play.
start.def_pos_team_score	integer	ESPN's def_pos_team_score value for the play state at the start of the play.
start.pos_score_diff	integer	ESPN's pos_score_diff value for the play state at the start of the play.
end.pos_team_score	integer	ESPN's pos_team_score value for the play state at the end of the play.
end.def_pos_team_score	integer	ESPN's def_pos_team_score value for the play state at the end of the play.
end.pos_score_diff	integer	ESPN's pos_score_diff value for the play state at the end of the play.
lag_pos_team	integer
lead_pos_team	integer
lead_pos_team2	integer	Value of pos_team 2 plays ahead, used for sequence-aware derivations.
pos_score_diff	integer
lag_pos_score_diff	integer
pos_score_pts	integer
pos_score_diff_start	integer
start.pos_team_receives_2H_kickoff	logical	ESPN's pos_team_receives_2H_kickoff value for the play state at the start of the play.
end.pos_team_receives_2H_kickoff	logical	ESPN's pos_team_receives_2H_kickoff value for the play state at the end of the play.
change_of_poss	logical
penalty_flag	logical
penalty_declined	logical
penalty_no_play	logical
penalty_offset	logical
penalty_1st_conv	logical
penalty_in_text	logical	True when the play description mentions a penalty.
penalty_detail	character
penalty_text	character
yds_penalty	character
penalty_count	integer	Number of penalties flagged on the play (0-4 observed).
penalty_declined_count	integer	Number of the flagged penalties that were declined.
penalty_all_declined	logical	Whether every penalty flagged on the play was declined.
penalty_enforcement	character	How the penalty was resolved: one of no_play, declined, offsetting, negating_foul, play_stands, unknown.
penalty_negated_play	logical	Whether the penalty negated the play's result.
sack	logical	Binary indicator for if the play ended in a sack.
int	logical
int_td	logical
completion	logical
pass_attempt	logical	Binary indicator for if the play was a pass attempt (includes sacks).
target	logical
pass_breakup	logical	True when a defender broke up the pass.
pass_td	logical
rush_td	logical
pass_depth	character	Thrown-pass depth parsed from ESPN play text ("short" or "deep"); null when the text omits it (sacks, screens, pre-2025 text).
pass_direction	character	Pass direction parsed from ESPN play text ("left", "middle", or "right"); null when the text omits it.
rush_direction	character	Rush direction parsed from ESPN play text ("left", "middle", or "right"); null when the text omits it.
turnover_vec	logical
offense_score_play	logical
defense_score_play	logical
downs_turnover	logical
yds_punted	integer
yds_punt_gained	integer
fg_attempt	logical	True when the play was a field-goal attempt.
fg_made	logical
yds_fg	integer
pos_unit	character
def_pos_unit	character
lead_play_type	character
sp	logical	Binary indicator for whether or not a score occurred on the play.
play	logical	Binary indicator: 1 if the play was a 'normal' play (including penalties), 0 otherwise.
scrimmage_play	logical	True when the play is a play from scrimmage rather than a special-teams or administrative row.
change_of_pos_team	logical
pos_score_diff_end	integer	Score differential from the possessing team's perspective at the end of the play.
fumble_lost	logical	Binary indicator for if the fumble was lost.
fumble_recovered	logical	True when a fumble on the play was recovered.
field_goal_result	character	String indicator for result of field goal attempt: made, missed, or blocked.
extra_point_result	character	String indicator for the result of the extra point attempt: good, failed, blocked, safety (touchback in defensive endzone is 1 point apparently), or aborted.
two_point_conv_result	character	String result of the two-point conversion attempt: success, failure, or safety (touchback in the defensive end zone).
kneel_down	logical	Whether the play is an offensive kneel, from explicit kneel text plus an end-of-half TEAM-rush heuristic.
qb_hurry	logical	Whether ESPN's play text says the quarterback was hurried into the throw ("hurried by ...").
xp_attempt	logical	Whether an extra-point kick was attempted on the play.
xp_made	logical	Whether the extra-point kick was successful.
two_point_attempt	logical	Binary indicator for two point conversion attempt.
defensive_two_point_attempt	logical	Binary indicator whether or not the defense was able to have an attempt on a two point conversion, this results following a turnover.
defensive_two_point_conv	logical	Binary indicator whether or not the defense successfully scored on the two point conversion.
two_point_pass	logical
two_point_rush	logical
yds_rushed	integer
yds_receiving	integer
yds_int_return	character
yds_kickoff	integer
yds_kickoff_return	integer
yds_punt_return	integer
yds_fumble_return	character
yds_sacked	integer
sack_players	character
xp_kicker_player_name	character	Name of the kicker attempting the extra point.
passer_player_name	character	String name for the player that attempted the pass.
rusher_player_name	character	String name for the player that attempted the run.
receiver_player_name	character	String name for the targeted receiver.
sack_player_name	character	String name of the player who recorded a solo sack.
sack_player_name2	character
pass_breakup_player_name	character
interception_player_name	character	String name for the player that intercepted the pass.
fg_kicker_player_name	character
fg_block_player_name	character
fg_return_player_name	character
kickoff_player_name	character
kickoff_return_player_name	character	Name of the player returning the kickoff, when the play was returned.
punter_player_name	character	String name for the punter.
punt_block_player_name	character
punt_return_player_name	character	Name of the player returning the punt, when the punt was returned.
punt_block_return_player_name	character
fumble_player_name	character
fumble_forced_player_name	character
fumble_recovered_player_name	character
kicking_team	integer	Team id of the kicking team on kickoff, punt, and field-goal plays.
return_team	integer	Team id of the returning side; set on interception, fumble, kickoff, punt, and blocked-kick returns.
fumble_or_muff	logical	Whether the play includes a fumble or a muffed kick or punt (widened beyond ESPN's fumble play types).
recovery_team	character	Team id parsed from the play text as recovering the fumble or muff.
recovery_team_2	character	Team id of the second recovery in a multi-recovery scramble, parsed from the play text.
penalty_spot_yardline	integer	Yard line (0-50) at which the penalty was spotted.
penalty_spot_side	character	Side of the field the penalty was spotted on: 'home', 'away' or 'mid' (midfield).
penalty_spot_yardsToEndzone	integer	Yards from the penalty spot to the end zone (0-100).
fumbling_team	character	Team id of the side that fumbled or muffed the ball, parsed from the play text.
int_turnover	logical	Whether the play is an interception giveaway.
pos_fumble_lost	logical	Whether the possession team fumbled and lost the ball.
def_fumble_lost	logical	Whether the defending team (e.g. a returner after a takeaway) fumbled and lost the ball back.
is_pos_team_turnover	logical	Whether the possession team committed a giveaway (interception or fumble lost).
is_def_pos_team_turnover	logical	Whether the defending team gave the ball back via a lost fumble.
is_turnover	logical	True when the play is a giveaway-based turnover (interception thrown or fumble lost); blocked kicks recovered by the defense are carried by the blocked-kick fields instead.
turnover_team	character	Team id charged with the giveaway on the play.
is_st_turnover	logical	Whether the giveaway happened on a special-teams play (kick or punt snap, or a return).
is_blocked_punt_turnover	logical	Blocked-punt possession loss (blocked-punt TD, or the defense recovered); kept out of is_turnover to match ESPN's giveaway-only box.
is_blocked_fg_turnover	logical	Blocked-field-goal possession loss (blocked-FG TD, or the defense recovered); kept out of is_turnover to match ESPN's giveaway-only box.
sack_team	integer	Team id credited with the sack (the defense).
interception_team	integer	Team id credited with the interception (the defense).
pass_breakup_team	integer	Team id credited with the pass breakup (the defense).
forced_fumble_team	integer	Team id credited with forcing the fumble -- the side opposite the fumbling player (the covering team on returns).
fumble_recovery_team	character	Team id that recovered the fumble or muff, from parsed text with a giveaway / own-recovery fallback.
punt_return_team	integer	Team id of the punt-returning side.
kick_return_team	integer	Team id of the kick-returning side.
fg_team	integer	Team id attempting the field goal (the kicking team).
punt_team	integer	Team id punting the ball (the kicking team).
penalized_team	integer	Team id the penalty was assessed against, from the home/away text resolver with a foul-direction fallback.
penalty_yards_signed	integer	Penalty yardage parsed from the play text with era-aware bounds; the printed sign is retained but is not a reliable enforcement direction.
penalty_side	character	Which side committed the penalty -- 'off' (offense) or 'def' (defense).
penalty_yards_net	integer	Net yardage assessed for the penalty, signed relative to the possession team (observed -25 to 25).
penalty_team_id	integer	Team id of the side that committed the penalty.
lateral_player_name	character
yds_lateral	character
yards_after_catch	character	Numeric value for distance in yards perpendicular to the yard line where the receiver made the reception to where the play ended.
air_yards	character	Numeric value for distance in yards perpendicular to the line of scrimmage at where the targeted receiver either caught or didn't catch the ball.
air_yardsToEndzone	character	Yards to the endzone at the catch spot, parsed from the 2025+ vendor catch-spot text; null before 2025 or when unresolvable.
new_down	integer	Down after the play, including any penalty enforcement.
new_distance	integer	Distance to go after the play, including any penalty enforcement.
middle_8	logical
rz_play	logical
under_2	logical	Whether the play began with two minutes or less remaining in the half.
goal_to_go	logical	Binary indicator for whether or not the posteam is in a goal down situation.
scoring_opp	logical
stuffed_run	logical
stopped_run	logical	True when the rush was stopped at or behind the line of scrimmage.
opportunity_run	logical
highlight_run	logical	True when the rush gained 8 or more yards.
adj_rush_yardage	integer	Rushing yards capped at 8, the input to the line-yards decomposition.
line_yards	double	Yards credited to the offensive line on a rush, using the standard sliding scale: 1.2x the capped yardage on a loss, all of it through 3 yards, half of each yard from 4 to 8, and a 5.5-yard ceiling beyond that.
second_level_yards	double	Rushing yards earned from 4 to 8, split evenly between line and carrier under the line-yards decomposition.
open_field_yards	integer	Rushing yards gained beyond 8, credited to the ball carrier rather than the line.
highlight_yards	double	Second-level plus open-field yards -- the yardage credited to the carrier.
opp_highlight_yards	double	Highlight yards earned on opportunity runs, isolating carrier production on carries where the blocking succeeded. Assets published before the 2026-08 fix are identically 0 here, because the inverted opportunity_run gate could never co-occur with non-zero highlight yards.
short_rush_success	logical	True when a short-yardage rush gained the yardage needed.
short_rush_attempt	logical	True when the play is a rush in a short-yardage situation.
power_rush_success	logical	True when a power rushing attempt gained the yardage needed.
power_rush_attempt	logical	True when the play is a short-yardage power rushing attempt.
early_down	logical	True when the play is a scrimmage play on first or second down.
late_down	logical	True when the play is a scrimmage play on third or fourth down.
early_down_pass	logical	True when the play is a pass on an early down.
early_down_rush	logical	True when the play is a rush on an early down.
late_down_pass	logical	True when the play is a pass on a late down.
late_down_rush	logical	True when the play is a rush on a late down.
standard_down	logical	True when the offense is on schedule for the series -- first down, second down needing fewer than 8, or third/fourth down needing fewer than 5.
passing_down	logical	True when the offense is behind schedule for the series -- second down needing 8 or more, or third/fourth down needing 5 or more.
TFL	logical	True when the play was a tackle for loss.
TFL_pass	logical	True when the play was a tackle for loss on a pass play (a sack).
TFL_rush	logical	True when the play was a tackle for loss on a rush play.
havoc	logical	True when the defense disrupted the play: a pass breakup, tackle for loss, interception or forced fumble.
first_down_yards	logical	Whether the play gained enough yardage to earn a first down.
first_down_penalty	logical	Binary indicator for if a penalty converted the first down.
first_down_earned	logical	Whether the play earned a first down by means other than yardage (e.g. by penalty).
new_series	logical
firstD_by_kickoff	logical
firstD_by_poss	logical
firstD_by_penalty	logical
firstD_by_yards	logical
start.pos_team_spread	double	ESPN's pos_team_spread value for the play state at the start of the play.
start.elapsed_share	double	ESPN's elapsed_share value for the play state at the start of the play.
start.spread_time	double	ESPN's spread_time value for the play state at the start of the play.
end.pos_team_spread	double	ESPN's pos_team_spread value for the play state at the end of the play.
end.elapsed_share	double	ESPN's elapsed_share value for the play state at the end of the play.
end.spread_time	double	ESPN's spread_time value for the play state at the end of the play.
pass_length	character	String indicator for pass length: short or deep.
pass_location	character	String indicator for pass location: left, middle, or right.
shotgun	integer	Binary indicator for whether or not the play was in shotgun formation.
no_huddle	integer	Binary indicator for whether or not the play was in no_huddle formation.
pass_middle	integer
down	integer	The down for the given play.
distance	integer
start.yardsToEndzone.touchback	integer	ESPN's yardsToEndzone.touchback value for the play state at the start of the play.
penalty_assessed_on_kickoff	logical	Whether a penalty was assessed on a kickoff; such plays take the kickoff/touchback win-probability handling.
EP_start_touchback	double	Expected points the offense would have had from a touchback on this play.
EP_start	double	Expected points for the offense at the start of the play.
EP_end	double	Expected points for the offense at the end of the play.
EP_penalty_cf	character	Counterfactual expected points for the penalty branch -- the EP had the alternative penalty outcome been taken (null unless a penalty decision existed).
penalty_cf_yardsToEndzone	character	Yards to the end zone in the counterfactual penalty branch.
lag_EP_end	double	Value of EP_end on the previous play, used for sequence-aware derivations.
lag_change_of_pos_team	logical
EP_between	double	Change in expected points across the play, before penalty adjustment.
EPA	double
def_EPA	double
EPA_scrimmage	double	EPA credited to the play on plays from scrimmage.
EPA_rush	double	EPA credited to the play on rush plays.
EPA_pass	double	EPA credited to the play on pass plays.
EPA_explosive	logical	True when the play was explosive.
EPA_non_explosive	double	EPA credited to the play on non-explosive plays.
EPA_explosive_pass	logical	True when the pass play was explosive.
EPA_explosive_rush	logical	True when the rush play was explosive.
first_down_created	logical	True when the play produced a first down for the offense.
EPA_success	logical	True when the play was successful by EPA.
EPA_success_early_down	logical	True when the play on an early down was successful by EPA.
EPA_success_early_down_pass	logical	True when the pass play on an early down was successful by EPA.
EPA_success_early_down_rush	logical	True when the rush play on an early down was successful by EPA.
EPA_success_late_down	logical	True when the play on a late down was successful by EPA.
EPA_success_late_down_pass	logical	True when the pass play on a late down was successful by EPA.
EPA_success_late_down_rush	logical	True when the rush play on a late down was successful by EPA.
EPA_success_standard_down	logical	True when the play on a standard down was successful by EPA.
EPA_success_passing_down	logical	True when the play on a passing down was successful by EPA.
EPA_success_pass	logical	True when the pass play was successful by EPA.
EPA_success_rush	logical	True when the rush play was successful by EPA.
EPA_success_EPA	double	EPA on successful plays.
EPA_success_standard_down_EPA	double	EPA on successful plays on a standard down.
EPA_success_passing_down_EPA	double	EPA on successful plays on a passing down.
EPA_success_pass_EPA	double	EPA on successful pass plays.
EPA_success_rush_EPA	double	EPA on successful rush plays.
EPA_middle_8_success	logical	True when the play in the middle eight was successful by EPA.
EPA_middle_8_success_pass	logical	True when the pass play in the middle eight was successful by EPA.
EPA_middle_8_success_rush	logical	True when the rush play in the middle eight was successful by EPA.
EPA_penalty	double	EPA credited to the play attributable to penalties.
EPA_penalty_direct	double	EPA attributable directly to the penalty on the play, separated from the EPA of the play itself (observed -11.7 to 8.05; null when no penalty applied).
EPA_sp	double	EPA credited to the play on special-teams plays.
EPA_fg	double	EPA credited to the play on field-goal attempts.
EPA_punt	double	EPA credited to the play on punt plays.
EPA_kickoff	double	EPA credited to the play on kickoff plays.
qb_epa	double	Gives QB credit for EPA for up to the point where a receiver lost a fumble after a completed catch and makes EPA work more like passing yards on plays with fumbles.
start.ExpScoreDiff_touchback	double	ESPN's ExpScoreDiff_touchback value for the play state at the start of the play.
start.ExpScoreDiff	double	ESPN's ExpScoreDiff value for the play state at the start of the play.
start.ExpScoreDiff_Time_Ratio_touchback	double	ESPN's ExpScoreDiff_Time_Ratio_touchback value for the play state at the start of the play.
start.ExpScoreDiff_Time_Ratio	double	ESPN's ExpScoreDiff_Time_Ratio value for the play state at the start of the play.
end.ExpScoreDiff	double	ESPN's ExpScoreDiff value for the play state at the end of the play.
end.ExpScoreDiff_Time_Ratio	double	ESPN's ExpScoreDiff_Time_Ratio value for the play state at the end of the play.
wp_before	double
wp_touchback	double	Win probability the offense would have had starting from a touchback.
wp_after	double
def_wp_before	double
home_wp_before	double
away_wp_before	double
lead_wp_before	double	Value of wp_before on the next play, used for sequence-aware derivations.
lead_wp_before2	double	Value of wp_before 2 plays ahead, used for sequence-aware derivations.
def_wp_after	double
home_wp_after	double
away_wp_after	double
wpa	double	Win probability added (WPA) for the posteam.
wp	double	Estimated win probability for the posteam given the current situation at the start of the given play.
vegas_wp	double	Estimated win probability for the posteam given the current situation at the start of the given play, incorporating pre-game Vegas line.
def_wp	double	Estimated win probability for the defteam.
home_wp	double	Estimated win probability for the home team.
away_wp	double	Estimated win probability for the away team.
wp_before_naive	double	Pre-snap possession-team win probability from the spread-free (naive) WP model.
wp_after_naive	double	End-of-play possession-team win probability from the naive model, after the game-logic adjustment chain.
wpa_naive	double	Win probability added on the play under the spread-free (naive) model.
def_wp_before_naive	double	Pre-snap defense win probability under the naive model (1 - wp_before_naive).
def_wp_after_naive	double	End-of-play defense win probability under the naive model.
home_wp_before_naive	double	Pre-snap naive win probability mapped to the home team.
home_wp_after_naive	double	End-of-play naive win probability mapped to the home team.
lead_wp_before_naive	double	Next play's pre-snap naive win probability, used in the end-of-half and change-of-possession adjustments.
lead_wp_before2_naive	double	Pre-snap naive win probability two plays ahead, used where the immediately following row is a non-play.
wp_touchback_naive	double	Naive-model win probability for the kickoff-touchback substitute state, used as the pre-snap WP on kickoffs.
away_wp_before_naive	double	Pre-snap naive win probability mapped to the away team.
away_wp_after_naive	double	End-of-play naive win probability mapped to the away team.
cp	character	Numeric value indicating the probability for a complete pass based on comparable game situations.
cpoe	character	For a single pass play this is 1 - cp when the pass was completed or 0 - cp when the pass was incomplete. Analyzed for a whole game or season an indicator for the passer how much over or under expectation his completion percentage was.
xpass	double	Probability of dropback scaled from 0 to 1.
pass_oe	double	Dropback percent over expected on a given play scaled from 0 to 100.
xyac_epa	character	Expected value of EPA gained after the catch, starting from where the catch was made. Zero yards after the catch would be listed as zero EPA.
xyac_mean_yardage	character	Average expected yards after the catch based on where the ball was caught.
xyac_median_yardage	character	Median expected yards after the catch based on where the ball was caught.
xyac_success	character	Probability play earns positive EPA (relative to where play started) based on where ball was caught.
xyac_fd	character	Probability play earns a first down based on where the ball was caught.
drive_start	double	Yard line at which the drive began.
drive_stopped	logical	True when the play ended the drive.
drive_play_index	integer	Sequence number of the play within its drive.
drive_offense_plays	integer	Offensive plays run on the drive.
prog_drive_EPA	double	Cumulative EPA accrued by the drive up to and including this play.
prog_drive_WPA	double	Cumulative win-probability added by the drive up to and including this play.
drive_offense_yards	integer	Offensive yards gained on the drive.
drive_total_yards	integer	Total yards gained on the drive.
fixed_drive	integer	Manually created drive number in a game.
fixed_drive_result	character	Manually created drive result.
series	integer	Starts at 1, each new first down increments, numbers shared across both teams NA: kickoffs, extra point/two point conversion attempts, non-plays, no posteam
series_result	character	Possible values: First down, Touchdown, Opp touchdown, Field goal, Missed field goal, Safety, Turnover, Punt, Turnover on downs, QB kneel, End of half
series_success	integer	1: scored touchdown, gained enough yards for first down.
go_wp	double	Win probability from going for it on fourth down: conversion-probability-weighted mean of the success and failure states (cfb4th port).
first_down_prob	double	Modeled probability of converting the fourth down when going for it.
wp_succeed	double	Mean win probability across yardage outcomes given the fourth-down attempt converts.
wp_fail	double	Mean win probability given the fourth-down attempt fails.
fg_make_prob	double
make_fg_wp	double	Win probability given the field-goal attempt is made.
miss_fg_wp	double	Win probability given the field-goal attempt misses.
fg_wp	double	Make-probability-weighted win probability of attempting the field goal.
punt_wp	double	Win probability of punting, from the bundled punt-outcome distribution.
go_boost	double	cfb4th's headline number: 100 * (go_wp - max(fg_wp, punt_wp)), in percentage points.
go_wp_diff	double	go_wp minus the recommended option's WP (0 when going for it is the recommendation, otherwise <= 0).
punt_wp_diff	double	punt_wp minus the recommended option's WP (0 when punting is the recommendation, otherwise <= 0).
fg_wp_diff	double	fg_wp minus the recommended option's WP (0 when the field goal is the recommendation, otherwise <= 0).
fourth_down_recommendation	character	Max-WP fourth-down choice among "go", "punt", and "field_goal".
two_pt_wp	double	Win probability of going for two: conversion-probability-weighted mean of the 2-point and 0-point outcomes (cfb4th port).
xp_wp	double
prob_2pt	double
two_pt_wp_diff	double	two_pt_wp minus xp_wp; positive favors going for two.
two_pt_recommendation	character	Point-after recommendation: "go_for_2" when two_pt_wp exceeds xp_wp, otherwise "kick_xp".
qbr_epa	double	EPA variant used as an input to the QBR calculation.
weight	double	Official weight, in pounds
non_fumble_sack	logical	True when the play was a sack that did not produce a fumble.
sack_epa	double	EPA credited to the play when it is a sack.
pass_epa	double	EPA credited to the play when it is a pass.
rush_epa	double	EPA credited to the play when it is a rush.
pen_epa	double	EPA attributable to a penalty on the play.
sack_weight	double	Weighting applied to the sack component of the play.
pass_weight	double	Weighting applied to the pass component of the play.
rush_weight	double	Weighting applied to the rush component of the play.
pen_weight	double	Weighting applied to the penalty component of the play.
action_play	logical	True when the play advanced the game state -- excludes timeouts, end-of-period markers and other non-action rows.
athlete_name	character
sack_player_id2	character	ESPN athlete id of the second sacker on a split sack (regex fallback for an ESPN sidecar blind spot).
passer_player_id	character	Unique identifier for the player that attempted the pass.
rusher_player_id	character	Unique identifier for the player that attempted the run.
receiver_player_id	character	Unique identifier for the receiver that was targeted on the pass.
punter_player_id	character	Unique identifier for the punter.
fg_kicker_player_id	character	ESPN athlete id of the field-goal kicker.
sack_player_id	character	Unique identifier of the player who recorded a solo sack.
punt_return_player_id	character	ESPN athlete id of the punt returner.
kickoff_return_player_id	character	ESPN athlete id of the kickoff returner.
interception_player_id	character	Unique identifier for the player that intercepted the pass.
pass_breakup_player_id	character
fumble_forced_player_id	character
fumble_recovered_player_id	character
fumble_player_id	character
punt_block_player_id	character	ESPN athlete id of the player who blocked the punt.
punt_block_return_player_id	character	ESPN athlete id of the player who returned the blocked punt.
kickoff_player_id	character	ESPN athlete id of the player kicking off.
fg_block_player_id	character	ESPN athlete id of the player who blocked the field goal.
fg_return_player_id	character	ESPN athlete id of the player who returned the blocked or missed field goal.
xp_kicker_player_id	character
ep	double	Using the scoring event probabilities, the estimated expected points with respect to the possession team for the given play.
epa	double	Expected points added (EPA) by the posteam for the given play.
ep_start	double
ep_end	double

Example

# For most use cases, call the high-level entry point instead. ``enrich_nfl_pbp`` scores EP, derives EPA, and adds WP/WPA/CP/CPOE in one shot on any nflverse-shape frame

    from sportsdataverse.nfl import load_nfl_pbp
    from sportsdataverse.nfl.ep_wp import enrich_nfl_pbp

    pbp = load_nfl_pbp([2023])
    enriched = enrich_nfl_pbp(pbp)
    print(enriched.select("game_id", "ep", "epa").head())

``calculate_epa`` directly requires ESPN-internal columns
(``EP_start``, ``EP_end``, ``EP_start_touchback``, ``type.text``,
etc.) produced by ``NFLPlayProcess``.  It is called internally by
``NFLPlayProcess.__process_epa`` and by the ``enrich_nfl_pbp``
orchestrator — a naked ``calculate_epa(load_nfl_pbp([2023]))``
will raise ``KeyError`` because those columns are absent from a
nflverse frame.