# How GGAB tracks a match

> How a badminton match becomes rally-by-rally, shot-by-shot data at GGAB: who tracks it, every step, how it's checked, and what's worked out by rule rather than by eye.

Source: https://www.getgoodatbadminton.com/docs/data-methodology
Updated: 2026-10-24
Answers: How does GGAB track a badminton match? / How accurate is GGAB's shot data? / Who tags the shots in GGAB's pro matches? / How is GGAB's data checked? / Is forced versus unforced decided by a person? / What is GGAB's data methodology?

Every match in GGAB, pro or your own, is tracked rally by rally and shot by shot by people watching the video. This page explains what gets recorded, who records it, how it's checked, and which values are worked out by a fixed rule instead of by eye. [How shots are classified](https://www.getgoodatbadminton.com/docs/shot-classification) has every shot type, with examples you can watch.

## What gets recorded

**For every rally:** when it started and ended in the video, who served, who won it, how it ended, and the score before it.

**For every shot:**

- the moment the shuttle was hit, and who hit it
- the shot's family (smash, drop, net and so on) and, where one applies, its variant (cut slice, spin net and so on)
- the side it was played on: forehand, backhand or around the head
- where it went: straight, middle or cross
- how high it was met, for net, lift, drive and block
- where it was placed, for serves
- whether it was deceptive
- how it ended the rally, for the last shot, and where an error went: into the net, out the back or out the sides

## Who tracks

GGAB's pro matches are tracked by GGAB's tracking team. Every analyst passes a tracking test, scored against a match that has been checked shot by shot, before they track live matches. Players can also tag their own matches by hand; those stay in their own account and are never part of the pro data.

## How a match is tracked

### Step 1: Time every shot

The analyst marks the moment each shot is hit and who hit it, rally by rally.

### Step 2: Classify every shot

Each shot gets its family, variant, side, direction and, where it applies, contact height and serve placement. Definitions and the lines between them are in [How shots are classified](https://www.getgoodatbadminton.com/docs/shot-classification).

### Step 3: Work out the rallies and the score

Rallies, outcomes and the score are worked out from the shots, by the rules below, not typed in.

### Step 4: Review the errors

For every rally that ended in an error, the analyst records where it went.

### Step 5: Finalize

GGAB's analysts can't finalize a match while any shot is missing a required field. A pro match must also end on the same score the broadcast shows, game by game: if the worked-out score drifts from the scoreboard, a rally is missing or a winner is wrong, and it's fixed before the match is finalized.

## How it's checked

**We track matches twice.** A second analyst tracks the match again from scratch, without seeing the first pass. Wherever the two disagree, an expert reviewer looks at that shot and decides, and the decision replaces what was there. Players see the first pass straight away; the corrections land as the review finishes.

Each pro match is in one of these states:

| State | Meaning |
| --- | --- |
| First pass | Tracked once; the second pass isn't done yet |
| Second pass | Both passes done; the differences are waiting for the expert review |
| Verified | An expert has checked it: every difference between the two passes decided, or the whole match tracked by an expert |

## What's worked out by rule

Some values aren't judged by the analyst at all. They follow from the shots, the same way every time:

| Value | The rule |
| --- | --- |
| Winner or error | If the side that hit the last shot serves the next rally, the last shot was a winner. If the other side serves, it was an error. |
| Forced or unforced | An error is **forced** when the shot right before it was a smash, kill, drive or brush. Otherwise it's **unforced**. |
| The score | Rolls forward from the rally winners. |
| Where a shot was hit from, and where it went | Follow from its family: a lift is hit from the front and sent to the back; a drop and a smash are hit from the back and land short. |
| Contact height on kills and brushes | Assumed above the tape, since both are played off a shuttle above it. |

Because forced and unforced come from a rule, comparing your own errors with a pro's works best with all errors together.

## Timing

A shot's time is the moment the analyst marked it being hit, in seconds into the match video. It's accurate to within a few frames. Pro matches are tracked from official broadcasts, and the examples on these pages open the official video at that moment.

## Pro match rules

Broadcast footage brings its own awkward cases. The settled calls:

- **The serve is always tagged,** even when the broadcast cuts away from it, placed where it would have been hit, by the server the score says.
- **A let isn't tagged.** The replayed point is the rally.
- **The camera misses a shot or two:** the analyst tags their best reading rather than leaving a gap. A missing shot distorts every rally-length and pattern number; one uncertain field distorts one.
- **In doubles, when it's unclear which partner hit it:** the analyst's best call.
- **An error whose destination isn't clear** counts as into the net. Only errors that land out the back or out the sides are recorded as anything else.
- **A match that ends early** (a retirement, an injury) is finalized as it stands.

## How the standard has changed

- **Contact height** and a **serve's variant** (short, long or drive) have been required on every match since 21 September 2026. Some matches tracked before then don't have contact height.
- Definitions change rarely, and when they do, this page and [How shots are classified](https://www.getgoodatbadminton.com/docs/shot-classification) change with them.

## Known limits

- **Doubles coverage is thinner than singles,** women's and mixed doubles especially.
- **Forced or unforced is a rule,** not a judgement of how much pressure there was.
- **Deception is rare,** marked only when the racket starts one shot and changes into another.

## Video

GGAB doesn't share or distribute match video. Where an example points at a shot, it opens the official broadcast at that moment.

## Related guides

- [How shots are classified](https://www.getgoodatbadminton.com/docs/shot-classification)
- [Connect Claude or ChatGPT](https://www.getgoodatbadminton.com/docs/connect-ai)
- [Glossary](https://www.getgoodatbadminton.com/docs/glossary)