A team only allows 2.3 goals per game. Impressive, right?
Not so fast.
Look closer: their goaltender has a GSAx of +18. Without him, they'd be giving up 2.9 goals per game. Their defense lets dangerous shots through constantly, but the goalie keeps pulling off miracles.
The day the goalie has an average game? The house of cards collapses.
That's exactly what xGA (Expected Goals Against) reveals. This metric measures a team's defensive quality independently of goaltender performance. And for NHL bettors, that's crucial information.
What Is xGA?
The Definition
xGA = Expected Goals Against
xGA measures the number of goals a team should concede, based on the volume and quality of shots they allow against.
xGA = Sum of goal probabilities from all opposing shots
The Difference from Actual Goals
| Metric | What It Measures |
|---|---|
| Goals Against (GA) | Goals actually conceded (outcome) |
| xGA | Goals that should have been conceded (process) |
The gap between the two = goaltender performance + luck.
GA < xGA → The goalie is bailing out the team (or luck)
GA > xGA → The goalie is underperforming (or bad luck)
GA ≈ xGA → Performance aligned with defensive quality
A Concrete Example
Team A — Over a full season:
| Metric | Value |
|---|---|
| xGA (expected goals against) | 185 |
| GA (actual goals against) | 165 |
| Difference | -20 |
This team conceded 20 fewer goals than expected. Why?
- Their goaltender overperformed (GSAx +20)
- Or they got lucky on opposing shots
The implication: If the goalie regresses toward the mean, they'll concede more goals.
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xGA vs xGF: The Complete Equation
Both Sides of the Puck
| Metric | What It Measures | Good Value |
|---|---|---|
| xGF (Expected Goals For) | Offensive quality | High |
| xGA (Expected Goals Against) | Defensive quality | Low |
| xGF - xGA | Overall differential | Positive |
The xG Differential
xG Differential = xGF - xGA
| xG Differential | Interpretation |
|---|---|
| > +0.50/game | Elite team |
| +0.20 to +0.50 | Good team |
| -0.20 to +0.20 | Average team |
| -0.50 to -0.20 | Below-average team |
| < -0.50/game | Struggling team |
Why this matters for betting:
A team with a strong xG Differential but mediocre results is likely unlucky. They'll improve -- that's a potential value bet.
A team with a poor xG Differential but strong results is likely lucky. They'll regress.
Breaking Down a Team's xGA
The Reference Scale
| xGA/game | Interpretation |
|---|---|
| < 2.30 | Elite defense |
| 2.30 - 2.60 | Good defense |
| 2.60 - 2.90 | Average defense |
| 2.90 - 3.20 | Weak defense |
| > 3.20 | Porous defense |
What xGA Tells You About a Team
| xGA | Actual GA | Meaning |
|---|---|---|
| 2.50 | 2.20 | Excellent or lucky goaltending |
| 2.50 | 2.50 | Performance aligned |
| 2.50 | 2.80 | Struggling or unlucky goaltending |
| 3.20 | 2.80 | Heroic goaltending masking terrible defense |
| 2.20 | 2.50 | Good defense, average goaltending |
The Classic Case: A Bubble Ready to Burst
Team X:
- xGA: 3.10/game (weak defense)
- Actual GA: 2.60/game (looks respectable)
- Goaltender GSAx: +15
This team is living on borrowed time.
The goalie is masking a porous defense.
Regression is inevitable.
Opportunity: Over on their games, especially against high-powered offenses.
The Components of xGA
xGA isn't a magic number. It stems from several measurable factors:
Factor #1: Shot Volume (Shots Against)
The more shots you allow, the higher your xGA.
| Shots Against/game | Impact on xGA |
|---|---|
| < 28 | Low volume, helps xGA |
| 28-32 | Average volume |
| > 32 | High volume, inflates xGA |
Factor #2: Shot Quality (Scoring Chances Against)
Not all shots are created equal. Scoring Chances are shots from dangerous areas of the ice.
| Scoring Chances Against/game | Interpretation |
|---|---|
| < 22 | Excellent zone defense |
| 22-26 | Solid defense |
| 26-30 | Average defense |
| > 30 | Porous defense |
Factor #3: High-Danger Chances Against (HDCA)
The most dangerous shots -- from the slot, on rebounds, during odd-man rushes.
| HDCA/game | Interpretation |
|---|---|
| < 8 | Elite defense |
| 8-10 | Good defense |
| 10-12 | Average defense |
| > 12 | Major defensive problem |
The Importance Hierarchy
HDCA > Scoring Chances Against > Shots Against
It's better to allow 35 shots from the perimeter than 25 shots with 15 of them from the slot.
Using xGA for Betting
Strategy #1: Compare xGA to Actual GA
Look for significant gaps:
| xGA/game | GA/game | Gap | Opportunity |
|---|---|---|---|
| 3.00 | 2.50 | -0.50 | Goalie saving the day, but regression likely → Over |
| 2.50 | 3.00 | +0.50 | Goalie underperforming → Under if goalie bounces back |
| 2.80 | 2.80 | 0 | No exploitable gap |
Strategy #2: Analyze the Offensive vs Defensive Matchup
For each game, cross-reference:
xGF Team A vs xGA Team B = Expected goals for A
xGF Team B vs xGA Team A = Expected goals for B
Estimated total = Sum of both
Example:
| Team | xGF/game | xGA/game |
|---|---|---|
| Toronto | 3.40 | 2.90 |
| Montreal | 2.60 | 3.30 |
Expected goals Toronto = f(xGF Toronto, xGA Montreal) ≈ 3.4 adjusted
Expected goals Montreal = f(xGF Montreal, xGA Toronto) ≈ 2.4 adjusted
Estimated total ≈ 5.8-6.2
Strategy #3: Identify "Fool's Gold" Teams
A team can have a strong record but weak underlying numbers (a low Corsi confirms it):
| Record | xGF | xGA | Diagnosis |
|---|---|---|---|
| 25-15-5 | 2.70 | 3.10 | Winning despite poor xG → Lucky |
| 18-20-7 | 3.30 | 2.60 | Losing despite strong xG → Unlucky |
The first team will likely regress (fewer wins ahead). The second team will likely improve (more wins ahead).
Strategy #4: Recent xGA vs Season xGA
Just like with Bullpen ERA, look at recent trends:
| xGA last 10 games | xGA season | Signal |
|---|---|---|
| << season | Defense in form | Under |
| >> season | Defense struggling | Over |
| ≈ season | Stable | No strong signal |
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xGA by Situation
5-on-5 (Even Strength)
This is the 'purest' xGA -- no special teams influence.
| xGA 5v5/60 min | Interpretation |
|---|---|
| < 2.00 | Elite 5v5 defense |
| 2.00-2.30 | Good defense |
| 2.30-2.60 | Average |
| > 2.60 | Structural problem |
Penalty Kill (PK)
xGA while shorthanded. Some teams excel on the PK; others are a sieve.
| PK xGA/60 min | Interpretation |
|---|---|
| < 6.00 | Excellent PK |
| 6.00-7.50 | Good PK |
| 7.50-9.00 | Average PK |
| > 9.00 | Weak PK |
Application: Facing a team with a strong Power Play against an opponent with a weak PK → potential Over.
Power Play (PP) -- Opponent's xGA While on PK
If your team has an elite PP and the opponent has a weak PK, expect goals on the man advantage.
We'll cover Power Play and Penalty Kill dynamics in more detail in an upcoming article.
Combining xGA and GSAx
The Power Combination
When analyzing a game, look at both:
| Team xGA | Goalie GSAx | Interpretation |
|---|---|---|
| Low (good) | Positive | Defensively elite, strong Under |
| Low (good) | Negative | Good defense but weak goaltending → Uncertain outcome |
| High (bad) | Positive | Porous defense saved by the goalie → Bubble |
| High (bad) | Negative | Defensive disaster → Strong Over |
Cross-Reference Example
Game: Panthers @ Senators
| Team | xGA/game | Goaltender | Season GSAx |
|---|---|---|---|
| Panthers | 2.40 | Bobrovsky | +12.5 |
| Senators | 3.25 | Forsberg | -4.2 |
Panthers analysis: - Strong defense (xGA 2.40) - Excellent goaltending (GSAx +12.5) - Hard to score against
Senators analysis: - Weak defense (xGA 3.25) - Struggling goaltending (GSAx -4.2) - Vulnerable
Prediction: Panthers will score easily. Ottawa will struggle. Under is risky because the Panthers will score. Moderate Over or Panthers -1.5 is the play.
The Limitations of xGA
Limitation #1: Doesn't Capture Full Context
xGA doesn't account for: - Game score effects (a leading team plays differently) - Fatigue (back-to-back situations) - Key defenseman injuries
Limitation #2: Depends on the Model Used
Different sites calculate xGA differently:
| Source | Model | Notes |
|---|---|---|
| MoneyPuck | Proprietary | Industry standard |
| Natural Stat Trick | Public | Slightly different |
| Evolving Hockey | RAPM-based | More complex |
Values can vary by 5-10% depending on the source. Use one consistent source.
Limitation #3: Small Samples Early in the Season
| Games Played | xGA Reliability |
|---|---|
| < 15 | Low |
| 15-30 | Moderate |
| 30-50 | Good |
| > 50 | High |
In October-November, take xGA numbers with a grain of salt.
Limitation #4: Doesn't Predict Changes
A team can change its defensive system, acquire a key defenseman at the trade deadline, or lose a player to injury. Past xGA won't reflect those changes.
Full Example: Analysis Using xGA
The Game
Hurricanes @ Blue Jackets -- January 20, 2026
The Data
| Team | xGF/game | xGA/game | Actual GA/game | Goaltender | GSAx |
|---|---|---|---|---|---|
| Carolina | 3.35 | 2.45 | 2.30 | Andersen | +8.5 |
| Columbus | 2.70 | 3.40 | 3.60 | Merzlikins | -6.2 |
The Analysis
Carolina: - Elite offense (xGF 3.35) - Strong defense (xGA 2.45) - Above-average goaltending (+8.5) - Actual GA (2.30) < xGA (2.45) → Goalie is helping - Complete team
Columbus: - Decent offense (xGF 2.70) - Porous defense (xGA 3.40) - Struggling goaltending (-6.2) - Actual GA (3.60) > xGA (3.40) → Goalie isn't helping - Defensively vulnerable
The Estimated Calculation
Expected goals Carolina:
- xGF Carolina: 3.35
- xGA Columbus: 3.40 (weak opposing defense)
- Adjustment: Carolina should score easily
- Estimate: ~3.5 goals
Expected goals Columbus:
- xGF Columbus: 2.70
- xGA Carolina: 2.45 (strong opposing defense)
- Goaltender Andersen: GSAx +8.5
- Estimate: ~2.0 goals
Estimated total: 5.5 goals
The Bookmaker Line
Total: O/U 6.0
Over: 1.88
Under: 1.94
The Verdict
- Our estimate: 5.5 goals
- Line: 6.0 goals
- Gap: 0.5 goals favoring the Under (slight)
Additional analysis: - The juice is on the Under (1.94 vs 1.88) - The gap is modest
Verdict: Marginal Under. It might be better to bet Carolina -1.5 given the talent disparity.
Where to Find xGA Data
Free Sources
| Source | URL | Data |
|---|---|---|
| MoneyPuck | moneypuck.com | xGF, xGA, xG%, all situations |
| Natural Stat Trick | naturalstattrick.com | xGA, Scoring Chances, HDCA |
| Hockey Reference | hockey-reference.com | Basic stats + some advanced |
How to Navigate MoneyPuck
1. Go to moneypuck.com
2. Click on "Teams"
3. Look at the "xGF/GP" and "xGA/GP" columns
4. Calculate the differential
5. Compare with actual GF/GP and GA/GP
How ProbWin Uses xGA
Our NHL model integrates xGA at multiple levels:
1. Season xGA for each team
2. Recent xGA trend (last 10-15 games)
3. Situational xGA (5v5, PP, PK)
4. Cross-referenced with goaltender GSAx
5. xGA vs actual GA comparison (luck/skill split)
6. Matchup adjustment based on opposing offense
This data feeds into our total estimate and NHL picks.
Check out our NHL picks to see this analysis in action.
Summary: xGA in 7 Key Points
| # | Key Takeaway |
|---|---|
| 1 | xGA = expected goals against, measures defensive quality |
| 2 | xGA < actual GA = goalie bailing out the team (regression likely) |
| 3 | xGA > actual GA = goalie underperforming (improvement possible) |
| 4 | Cross-reference xGA with GSAx for the full picture |
| 5 | Look at situational xGA (5v5, PK) |
| 6 | Recent xGA vs season xGA reveals trends |
| 7 | Compare opponent xGF vs team xGA to estimate goals |
What's Next
You now know how to evaluate defensive quality with xGA and goaltending with GSAx. But before placing your bet, there's one crucial question left: who's in net tonight?
Find out why confirmed starting goaltender information is as important in NHL as the confirmed pitcher in MLB.
