CTG Pro Data Feed

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Chances ​

The chances section in the markings response contains an object for each "chance". A chance is a segment of the game where the offense has the opportunity to score.

Overview ​

Defining a chance is a little tricky. We can explain it by first explaining possessions.

We define a possession as starting when a team gets the ball and ending when they lose the ball (or the period ends). So one team starts with the ball, and then if they score, turn it over, miss a shot and don’t get an offensive rebound, or make free throws, the other team gets the ball, and that possession ends. If a team misses a shot but gets the offensive rebound, it doesn’t create a new possession, it just continues the prior possession.

We can split a possession into smaller segments that basically chop it up based on these continuous stretches of play with no stoppage, or a “chance” to score. So let’s say a team gets the ball, then draws a non-shooting foul. The game has stopped. The beginning of the possession until that whistle is one chance. The next chance would start when the ball is given to the inbounder to inbound. It’s a continuation of the prior possession but a new “chance”.

Similarly, if a team misses a jump shot but gets an offensive rebound, that would start a new chance but not a new possession. So the prior chance would end with the offensive rebound and a new chance would start with an offensive rebound.

NOTE

A chance, by definition, should not contain more than one chance ending event, i.e. it cannot have both a field goal attempt and a turnover in the same chance. In a situation where the shot clock expires as the ball is in the air and the ball never hits the rim, for example, the shot is in one chance, then a new chance is created for the shot clock violation right after.

An important feature of chances is that a substitution cannot occur during the chance, since it is a stretch of continuous gameplay, which means the set of players on the court must stay the same throughout the chance.

For more in-depth details on exactly how we start and stop chances, see the section below on Chance Start and End Timing.

Sample Response ​

json
{
  "markings": {
    "chances": [
      {
        "chance_id_ctg": "chance_51bfc1fda2cc0deb125bee9988859667",
        "chance_outcome": "fg2m",
        "chance_start_type": "jump_ball",
        "defense_players": [
          1630180,
          1630529,
          1630530,
          1642847,
          1642852
        ],
        "defensive_team_id_nba": 1610612740,
        "end_game_clock": 708.0,
        "end_he_frame": 806,
        "end_shot_clock": 13.0,
        "end_wall_clock": "2025-12-23T01:10:47.889+00:00",
        "fg_dreb": 0,
        "fg_oreb": 0,
        "fga": 1,
        "fga_pts": 2,
        "fgm": 1,
        "frontcourt_he_frame": 414,
        "frontcourt_wall_clock": "2025-12-23T01:10:41.356+00:00",
        "fta": 0,
        "ftm": 0,
        "game_id_nba": "0022500404",
        "in_garbage_time": false,
        "is_after_timeout": true,
        "is_shooter_fouled": false,
        "is_shot_blocked": false,
        "is_shot_made": true,
        "led_to_offensive_rebound": null,
        "offense_players": [
          1629023,
          1642843,
          1642948,
          203076,
          1630230
        ],
        "offensive_team_id_nba": 1610612742,
        "period": 1,
        "possession_id_ctg": "possession_640fb5737252cbe98b4f4a70dcee9d8f",
        "shot_location": "rim",
        "start_game_clock": 720.0,
        "start_he_frame": 118,
        "start_score_away": 0,
        "start_score_home": 0,
        "start_shot_clock": 24.0,
        "start_wall_clock": "2025-12-23T01:10:36.423+00:00",
        "tov": 0
      }
    ]
  }
}

Fields ​

Identifiers ​

game_id_nba ​

Type: string

NBA game ID

chance_id_ctg ​

Type: string

CTG-generated unique chance ID

possession_id_ctg ​

Type: string

CTG-generated possession ID that this chance belongs to

offensive_team_id_nba ​

Type: integer

NBA team ID of the team on offense

defensive_team_id_nba ​

Type: integer

NBA team ID of the team on defense

Lineups ​

offense_players ​

Type: array[integer]

Array of NBA player IDs for the five players on the court on offense during this chance.

defense_players ​

Type: array[integer]

Array of NBA player IDs for the five players on the court on defense during this chance.

Context ​

chance_start_type ​

Type: string

How the chance began, taken from one of the following options.

  • jump_ball: Tip-off or jump ball situation
  • fgm: Chance begins immediately after a made field goal (inbound after made basket)
  • ftm: Chance begins immediately after a made free throw sequence (inbound after made free throw)
  • steal: Gained possession via a live-ball turnover
  • fg_dreb: Defensive rebound after a missed field goal
  • fg_dreb_block: Defensive rebound after a blocked shot
  • fg_oreb: Offensive rebound after a missed field goal
  • ft_dreb: Defensive rebound after a missed free throw
  • ft_oreb: Offensive rebound after a missed free throw
  • baseline_inbounds: Chance begins on a dead-ball inbound from the frontcourt baseline
  • sideline_inbounds: Chance begins on a dead-ball inbound from the frontcourt sideline
  • backcourt_inbounds: Chance begins on a dead-ball inbound in the backcourt (sideline or baseline)

chance_outcome ​

Type: string

The outcome of the chance, taken from one of the following options.

Shot results:

  • fg2m: Made 2-point field goal
  • fg2x: Missed 2-point field goal
  • fg3m: Made 3-point field goal
  • fg3x: Missed 3-point field goal
  • heave: A shot designated as an official heave by the scorer
  • fg2m_fouled: Made 2-point field goal where the shooter was fouled (and-one)
  • fg3m_fouled: Made 3-point field goal where the shooter was fouled (and-one)

Turnovers:

  • steal: Live-ball turnover
  • deadball_turnover: Turnover that stops the clock and requires an inbounds (e.g. traveling, offensive foul, etc.)

Fouls:

  • shooting_foul: Shooting foul on an attempt (not an and-one make)
  • non-shooting_foul: Personal foul not associated with a shot, and not resulting in free throws
  • non-shooting_foul_bonus: Non-shooting foul that results in free throws due to the bonus
  • transition_take_foul: Transition take foul
  • away_from_the_play_foul: Away-from-the-play foul
  • clear_path_foul: Clear path foul
  • flagrant_foul: Flagrant foul (type 1 or type 2)
  • offensive_foul: Offensive foul
  • technical_foul: Technical foul
  • technical_defensive_three_second_foul: Defensive 3-second technical foul

Other endings / stoppages:

  • violation: Clock stops due to a violation
  • timeout: Chance ends due to a timeout
  • out_of_bounds_retain: Ball goes out of bounds and the offense retains possession
  • jump_ball: Chance ends in a jump ball situation
  • end_period: Period ended
  • other_stoppage: Any other stoppage types not covered above

is_after_timeout ​

Type: boolean

true if this chance immediately follows a timeout

Score ​

start_score_home ​

Type: integer

Score of the home team at the start of the chance

start_score_away ​

Type: integer

Score of the away team at the start of the chance

Timing ​

period ​

Type: integer

Period in which the chance occurred. Overtime would be period 5, double overtime period 6, etc.

start_he_frame ​

Type: integer

Hawk-Eye frame when chance began

start_wall_clock ​

Type: string

UTC timestamp when chance began

start_game_clock ​

Type: float

Game clock (seconds remaining) when chance began

start_shot_clock ​

Type: float

Shot clock when chance began. null if shot clock is off at the end of the quarter.

end_he_frame ​

Type: integer

Hawk-Eye frame when chance ended

end_wall_clock ​

Type: string

UTC timestamp when chance ended

end_game_clock ​

Type: float

Game clock when chance ended

end_shot_clock ​

Type: float

Shot clock when chance ended. null if shot clock is off at the end of the quarter.

frontcourt_he_frame ​

Type: integer

Hawk-Eye frame when ball first crossed halfcourt into the frontcourt. null if the ball never crosses halfcourt during the chance.

NOTE

This does not require a player to be in possession of the ball, it just the first time the x-coordinate of the ball crosses sides of the court in this chance, even if it's in mid-air.

frontcourt_wall_clock ​

Type: string

UTC timestamp corresponding to frontcourt_he_frame. null if the ball never crosses halfcourt.

in_garbage_time ​

Type: boolean

true if this chance occurred during "garbage time".

We use a definition of garbage time that is as objective as possible and generally matches up with most people's perception of when garbage time starts: when the game is out of hand, both teams have subbed out most of their starters, and the game never gets close again.

The Specific Definition

The exact definition CTG uses is: the game has to be in the 4th quarter, the score differential has to be >= 25 for minutes 12-9, >= 20 for minutes 9-6, and >= 10 for the remainder of the quarter. Additionally, there have to be two or fewer starters on the floor combined between the two teams.

Importantly, the game can never go back to being non-garbage time, or this clock resets. For example, if it's a 30 point game to start the 4th quarter, but one team comes back and pulls the game within 8, that comeback is not counted as garbage time. If the leading team regains control and expands the lead back out, garbage time would start when the score went back above 10.

This might not capture all of what we'd call garbage time, but it seems important to err on the side of caution and not mistakenly filter out any game time that we would not consider garbage time.

Chance Outcomes ​

These fields describe the outcome of the chance.

is_shot_made ​

Type: boolean

true if the shot was made, false if it was missed. null if no shot was taken.

is_shot_blocked ​

Type: boolean

true if the shot was blocked. null if no shot was taken.

is_shooter_fouled ​

Type: boolean

true if the shooter was fouled during the shot attempt. null if no shot was taken.

led_to_offensive_rebound ​

Type: boolean

true if a missed shot was rebounded by the offensive team. null if no shot was taken or if the shot was made.

fga_pts ​

Type: integer

Points scored on the field goal attempt (2 or 3 for made shots, 0 for misses). null if no shot was taken or if the chance has not yet been processed into the application layer.

fgm ​

Type: integer

Field goals made. 1 if the shot was made, 0 otherwise. null if no shot was taken or if the chance has not yet been processed into the application layer.

fga ​

Type: integer

Field goal attempts. 1 if a shot was attempted (not including shooting fouls without a shot), 0 otherwise. null if no shot was taken or if the chance has not yet been processed into the application layer.

ftm ​

Type: integer

Free throws made during this chance. null if the chance has not yet been processed into the application layer.

fta ​

Type: integer

Free throw attempts during this chance. null if the chance has not yet been processed into the application layer.

tov ​

Type: integer

Turnovers. 1 if the chance ended in a turnover, 0 otherwise. null if the chance has not yet been processed into the application layer.

fg_dreb ​

Type: integer

Defensive rebounds on field goal attempts. 1 if the defense rebounded a missed field goal, 0 otherwise. null if the chance has not yet been processed into the application layer.

fg_oreb ​

Type: integer

Offensive rebounds on field goal attempts. 1 if the offense rebounded a missed field goal, 0 otherwise. null if the chance has not yet been processed into the application layer.

Shot Location ​

shot_location ​

Type: string

The court zone where the shot was taken, one of the following values:

  • rim: At-rim shots (typically within ~4 feet of the basket)
  • short mid: Short mid-range shots (~4-14 feet from the basket)
  • long mid: Long mid-range shots (~14+ feet, inside the three-point line)
  • corner three: Three-point shots from the corner
  • non corner three: Three-point shots from above the break
  • heave: Full-court or half-court heave attempts

null if no shot was taken.

Chance Start and End Timing ​

There are many decisions to make around when specifically to start and end a chance. The CTG Pro Data Feed utilizes the 3D data where possible to attempt precise placements of these start and end frames.

Here is how chance boundaries are determined:

  • Jump balls: The chance starts the first time a player touches the ball with the game clock running after the jump ball.
  • Inbounds plays: The chance starts when the ball is in the hands of the inbounder and they have at least one foot out of bounds.
  • Fouls: The chance ends when the clock stops. If there are no free throws, the next chance starts following the inbounds timing described above.
    • For an and-one, the chance ends when the clock stops, not when the shot goes in.
  • Made shots: The chance ends when the top of the ball first drops below rim height, representing the moment the ball goes through the rim. The next chance starts when the inbounder has the ball out of bounds and is ready to inbound.
  • Missed shots:
    • If a player rebounds the ball, the chance ends when the ball is first touched by a potential rebounder. The next chance starts at the same frame.
    • If the ball goes out of bounds (even if touched first), the chance ends when the ball goes out of bounds and the clock stops. The next chance starts following the inbounds timing above.
    • If a loose ball foul occurs before the rebound is secured, the chance ends when the clock stops. The next chance starts at the same frame and ends one frame later, effectively creating a chance that only includes the foul. (We do this because in theory, a loose ball foul on a rebound like this is a scoring opportunity if the fouled team happened to be in the bonus.) The chance after that starts following the inbound rules above, or free throw rules noted below.
    • Blocked shots are treated like shots hitting the rim, with the same timing logic applying afterward.
  • Fouls resulting in free throws: The chance ends at the clock stopping as a result of the foul. The subsequent chance starts following the same rules as for field goal attempts: if the final free throw is made, the next chance starts when the inbounder has the ball with one foot out, and if the final free throw is missed the next chance starts following the rebound rules.
  • Live ball turnovers: The chance ends when the ball is first touched by the team that gains possession, and the next chance starts at the same frame.
    • That means in situations where there is a loose ball where both teams may deflect the ball but the defense ultimately gains possession, the prior chance ends and the next chance begins at the first frame where the defense touches the ball around the time of the turnover.