IHM Knowledge Center
What Does PDO Mean in Hockey?
Why do some teams suddenly overperform or underperform despite similar play, and how does PDO explain it?
Editor: Coach Mark • Updated: April 26, 2026
Short Answer
PDO is the sum of a team’s shooting percentage and save percentage. It is used to evaluate whether results are sustainable or influenced by short-term variation often described as luck.
Full Explanation
PDO is one of the simplest but most important concepts in hockey analytics. It combines two key factors:
- Shooting percentage
- Save percentage
When added together, these create a number that typically sits around 100 over time.
If a team has a PDO significantly above 100, it usually means that either their shooting percentage, save percentage, or both are performing at an unusually high level.
If PDO is below 100, the team may be experiencing poor finishing, weak goaltending, or both.
The key idea is that these numbers tend to move back toward the average over time.
How PDO Reflects Sustainability
PDO is often used to evaluate whether a team’s performance is sustainable.
A team with a very high PDO may be winning games, but that success may not last if it is driven by unusually high shooting efficiency or exceptional goaltending performance.
A team with a low PDO may be losing, but could improve if percentages return to normal levels.
This is why PDO is often associated with regression, meaning results moving back toward expected levels.
NHL vs IIHF Context
PDO is used most commonly in NHL analytics, where large sample sizes make trends easier to identify.
In IIHF tournaments, smaller sample sizes can create more extreme PDO values because fewer games increase variability.
Despite this, the principle remains the same across all levels of hockey.
Why PDO Is Controversial
PDO is controversial because it is often interpreted as a pure “luck” stat.
Fans may assume that a high PDO means a team is simply lucky, but coaches understand that factors like shot quality, defensive structure, and goaltending skill also influence these numbers.
The disagreement comes from how much weight should be given to randomness versus skill.
PDO does not eliminate skill. It highlights when results may be inflated or suppressed relative to typical expectations.
Edge Case: Consistently High PDO Teams
Some teams maintain higher PDO values over longer periods.
This can happen when:
- The team generates high-quality scoring chances
- Goaltending performance is consistently strong
- Defensive structure limits dangerous shots against
In this case, a higher PDO may reflect real strength rather than pure variance.
However, extreme values are still difficult to maintain over long periods.
IHM Signal System: How to Read PDO
To interpret PDO correctly, focus on these signals:
- Shooting quality: Are goals coming from dangerous areas?
- Goaltending form: Is performance consistent or fluctuating?
- Defensive structure: Are shots against controlled?
- Sample size: Short vs long-term trends
Trigger-level rule:
If a team has a PDO far above 100 without elite chance quality or strong defensive structure, regression is almost always expected.
This is a key indicator that results may not be sustainable.
IHM Insight: Why PDO Is Misunderstood
PDO is often misunderstood because it is labeled as a “luck stat.”
In reality, it reflects a combination of skill and variation.
Strong teams can influence PDO through shot quality and defensive play, but extreme values are rarely maintained without some level of statistical fluctuation.
Understanding this balance is critical for proper analysis.
Mini Q&A
What does PDO measure?
It measures combined shooting and save efficiency.
What is a normal PDO?
Around 100 over time.
Is high PDO always good?
Short term yes, but it may not last.
What does low PDO mean?
Underperformance that may improve.
Is PDO pure luck?
No, it includes both skill and variation.
Why This Rule Exists
PDO exists to help identify when results may not match underlying performance.
It provides a simple way to evaluate whether teams are overperforming or underperforming relative to typical expectations.
Key Takeaways
- PDO combines shooting and save percentage
- 100 is the long-term baseline
- High PDO may indicate overperformance
- Low PDO may indicate underperformance
- Context is required for accurate interpretation