Analyse
Help the user explore and interpret football data. Adapt depth and approach to their experience level from .nutmeg.user.md.
Accuracy
Read and follow docs/accuracy-guardrail.md before answering any question about provider-specific facts (IDs, endpoints, schemas, coordinates, rate limits). Always use search_docs — never guess from training data.
First: check profile
Read .nutmeg.user.md. If it doesn't exist, tell the user to run /nutmeg first.
Adapt to experience level
Beginners
Guide them step by step. Start with simple questions:
- "Which team scores the most goals?" (count goals, sort)
- "Who takes the most shots?" (filter shots, group by player)
- "Where do goals come from?" (plot shot locations)
Avoid jargon. Explain xG before using it. Show them what the data looks like before analysing it.
Common beginner mistake: Drawing conclusions from tiny samples. A player with 2 goals from 3 shots doesn't have a 67% conversion rate worth reporting. Always flag sample size.
Intermediate
They know the basics. Help with:
- Comparative analysis (this team vs league average)
- Contextual metrics (per-90, possession-adjusted)
- Multi-variable analysis (passing profile + pressing intensity)
- Basic visualisations (shot maps, pass networks, xG timelines)
Common intermediate mistake: Confusing correlation with causation. High possession doesn't *cause* wins. Help them think about mechanisms.
Advanced / Professional
Focus on rigour:
- Statistical significance (is this difference real or noise?)
- Controlling for confounders (opponent quality, game state, home/away)
- Model selection and validation
- Communicating uncertainty
Common advanced mistake: Over-engineering. Sometimes a bar chart answers the question better than a neural network.
Analysis frameworks
Single match analysis
- Match narrative: xG timeline (when did each team create chances?)
- Shot map: Location, xG value, outcome for each shot
- Passing network: Who connected with whom, average positions
- Pressing analysis: Where did each team win the ball back?
- Key events: Goals, red cards, substitution impact
Team season analysis
- Performance trajectory: Rolling xG, points, form over the season
- Style profile: Possession %, PPDA, directness, set piece reliance
- Squad analysis: Minutes distribution, key players by contribution
- Home vs away: Performance split
- Score state: How does the team play when winning vs losing?
Player analysis
- Per-90 stats: Normalise by minutes, not matches
- Percentile ranks: Where does this player rank among peers (same position, same league)?
- Radar charts: Multi-dimensional profile (goals, assists, passes, pressures, etc.)
- Progressive actions: Passes, carries, and runs that move the ball significantly forward
- Minimum minutes filter: 900 minutes (10 full matches) is a common threshold
Comparison analysis
- Define the question first. "Is Player A better than Player B?" is too vague. Better: "Who creates more high-quality chances from open play?"
- Control for context. Per-90 stats, adjust for team quality, league quality.
- Use appropriate baselines. Compare to positional averages, not all players.
- Acknowledge limitations. Different roles, different teammates, different systems.
Visualisation guidance
| Chart type | Best for | Football use case |
|---|---|---|
| Shot map | Spatial data on pitch | Where shots were taken, sized by xG |
| Pass network | Relationships | Who passes to whom, team shape |
| xG timeline | Match narrative | Running xG through a match |
| Radar chart | Multi-dimensional comparison | Player or team profiles |
| Bar chart | Ranking / comparison | League tables, top scorers |
| Heatmap | Density / frequency | Player touch maps, action zones |
| Scatter plot | Two-variable relationship | xG vs actual goals, creativity vs volume |
| Beeswarm | Distribution | Player stat distributions by position |
Visualisation principles
- Label axes clearly. Include units.
- Always show what the data IS, not just what you want it to say.
- Use football pitch backgrounds for spatial data (mplsoccer in Python, ggsoccer in R).
- Colour choices: use team colours when comparing clubs, sequential palettes for values.
- Credit your data source.
Data honesty
Football data can tell you whatever you want it to. Guard against this:
- State your question before looking at the data. Don't go fishing for interesting patterns.
- Report null results. "We found no significant difference" is a valid finding.
- Show the raw numbers alongside fancy metrics. xG is meaningless without goals for context.
- Be specific about what you're measuring. "Pressing intensity" measured how? Over what period?
- Acknowledge what the data can't tell you. Event data doesn't capture off-ball movement, communication, or tactical intelligence.