Chapter 14: Key Takeaways
Set Piece Analytics - Essential Concepts
Core Principles
1. Set Pieces Are Analytically Tractable
Unlike open play, set pieces offer: - Controlled starting conditions: Dead-ball situations with known positions - Repeatability: Same scenarios can be practiced and optimized - Clear measurement: Discrete events with identifiable outcomes - High leverage: 25-35% of goals come from set pieces
2. The Value Proposition
| Set Piece Type | % of Goals | Typical per Season | Improvement Potential |
|---|---|---|---|
| Corners | 8-12% | 6-10 | +2-4 goals |
| Indirect FKs | 5-8% | 4-6 | +1-2 goals |
| Direct FKs | 2-4% | 1.5-3 | +0.5-1 goals |
| Penalties | 6-9% | 5-7 | +1-2 goals |
| Throw-ins | 1-2% | 0.5-1.5 | +0.5-1 goals |
A 10-15% improvement in set piece effectiveness can yield 3-5 additional goals per season.
Corner Kick Analysis
Key Metrics
- Shot rate: Corners generating shots (avg ~20-25%)
- xG per corner: Expected goals per delivery (avg ~0.03-0.04)
- Conversion rate: Goals per corner (avg ~2.5-3%)
- First contact win rate: Attacking team winning initial header
Delivery Classification
| Delivery Type | Best For | Expected Value |
|---|---|---|
| Inswinger to near post | Quick headers | 0.04-0.06 xG |
| Outswinger to far post | Target man | 0.03-0.05 xG |
| Short corner | Technical teams | 0.04-0.06 xG |
| Driven | Creating chaos | 0.03-0.04 xG |
Critical Success Factor
Personnel-delivery matching: Align delivery type with player strengths. An elite aerial player needs deliveries to their optimal zone.
Free Kick Analysis
Direct Free Kicks
| Zone | Distance | xG Range |
|---|---|---|
| Prime | 18-22m, central | 0.06-0.10 |
| Good | 22-28m, central | 0.03-0.06 |
| Moderate | 18-25m, wide | 0.02-0.04 |
| Marginal | 28-35m | 0.01-0.03 |
Key Insight
Top corner targets convert at ~90% but have higher miss-frame risk. Bottom corners convert at ~80% with lower risk. Mid-height shots are the worst option (50-60% save rate).
Indirect Free Kicks
Treat as positioned corners with more delivery options: - Standard cross into box - Short combinations - Lay-off for edge-of-box shot
Penalty Analysis
The Numbers
- League conversion: ~76-78%
- Tournament conversion: ~73-75%
- Top corner conversion: ~90%
- Bottom corner conversion: ~76-80%
- Mid-height conversion: ~50-57%
Game Theory Application
Optimal strategy is mixed: No predictable pattern that goalkeepers can exploit.
| Factor | Recommendation |
|---|---|
| Placement | Vary between corners |
| Timing | Consistent run-up |
| GK reading | Study opponent tendencies |
Shootout Dynamics
- Shooting first: ~54% win rate
- Conversion declines: Kick 5 at ~65% vs. Kick 1 at ~74%
- "Must score" pressure: ~10% conversion reduction
Throw-in Analysis
The Overlooked Opportunity
- Frequency: 40-50 per match (most common set piece)
- Attacking throw-ins: High-value opportunities often ignored
- Long throws: Function like additional corners
Key Metrics
| Metric | Regular Throw | Long Throw |
|---|---|---|
| Shot rate | 2-3% | 12-18% |
| xG generated | 0.001 | 0.02-0.04 |
| Goal rate | 0.1% | 1-2% |
Long throw specialists provide measurable attacking value.
Defensive Set Piece Analysis
Critical Vulnerabilities
- Near post weakness: Poor marking of near post runs
- Second ball reactions: Failure to clear rebounds
- Aerial mismatches: Key attacker vs. weak marker
- Set piece tracking: Losing runners during delivery
Defensive Structure Options
| System | Pros | Cons |
|---|---|---|
| Zonal | Covers space, consistent | Vulnerable to movement |
| Man-marking | Tracks runners | Can be pulled out of position |
| Hybrid | Flexible | Requires coordination |
Expected Goals from Set Pieces
Why Separate Models?
Standard xG models may not accurately value set piece shots due to: - Different defensive structures - Different shot contexts (headers from crosses) - Different goalkeeper positioning
Building Set Piece xG
Key features for set piece xG models: - Distance to goal - Angle to goal - Body part (header vs. foot) - Set piece type (corner vs. free kick) - Location in box
Pattern Recognition
Clustering Approach
Use unsupervised learning to: 1. Group similar set piece routines 2. Identify effective patterns 3. Map opponent tendencies 4. Develop counter-strategies
Opponent Scouting
Pre-match preparation should include: - Delivery type distribution - Target zone preferences - Key personnel - Defensive structure - Vulnerable zones
Practical Implementation
Minimum Viable Analysis
For any team, start with:
- Calculate basic metrics: Corner/FK conversion rates
- Classify deliveries: Map delivery type distribution
- Track outcomes: Associate shots with set pieces
- Identify personnel strengths: Who wins aerial duels?
- Opponent scouting: Basic tendency analysis
Advanced Analysis
With more resources:
- Build custom xG models for set pieces
- Use clustering to identify patterns
- Implement real-time tracking of opponent adjustments
- Integrate video analysis with statistical insights
Essential Formulas
Corner xG Calculation
xG_corner = Σ P(shot_i) × xG(shot_i | location, type)
Penalty Expected Value (Game Theory)
E[Goal] = Σ_s Σ_d P(shot=s) × P(dive=d) × P(goal|s,d)
Set Piece Conversion Rate
CR = Goals_from_set_pieces / Total_set_piece_opportunities
Possession Retention
Retention = Successful_set_pieces / Total_set_pieces
Common Mistakes to Avoid
- Ignoring personnel matching: Delivering to zones where your best players aren't positioned
- Over-complicating routines: Simple, well-executed beats complex and confused
- Neglecting defense: Set piece defense is equally important
- Small sample conclusions: Set piece outcomes are variable; large samples needed
- Static analysis: Opponents adapt; continuous monitoring required
Tools and Technologies
Data Sources
- StatsBomb (event data with set piece detail)
- Opta (set piece classifications)
- Tracking data (player movement during set pieces)
Analysis Tools
- Python: pandas, scikit-learn for analysis
- mplsoccer: Pitch visualization
- Custom models: Set piece-specific xG
Summary Checklist
Before your next match:
- [ ] Calculate your team's set piece conversion rates
- [ ] Identify your best aerial players and their optimal zones
- [ ] Analyze opponent set piece defensive structure
- [ ] Prepare 2-3 corner routine variations
- [ ] Brief penalty takers on opponent GK tendencies
- [ ] Identify opponent set piece threats defensively
- [ ] Consider long throw opportunities if applicable
Looking Ahead
The next chapter explores Player Performance Metrics, building on set piece analysis to develop comprehensive frameworks for evaluating individual player contributions across all aspects of play.