Shot differential measures the difference between the number of shots on goal an NHL team generates and the number it allows.
Quick Summary
Shot differential measures the difference between official shots on goal for and against.
The formula is:
- Shots on goal for minus shots on goal against
Daily Rink Form can calculate the metric across:
- Season to date
- Last 5
- Last 10
- Last 20
- Home games
- Road games
- Schedule-condition splits
If a team generates more shots on goal than it allows, the result is positive. If it allows more shots on goal than it generates, the result is negative. If both totals are equal, the differential is zero.
Shot differential provides information about shot volume that goal differential and record do not show.
How Daily Rink Form defines a shot
Daily Rink Form uses official shots on goal. A shot on goal is an attempt recorded by the official game statistics as requiring a save or resulting in a goal.
The standard shot-differential metric does not include:
- Missed shots
- Blocked shots
- Total shot attempts
- Corsi
- Fenwick
- Expected goals
These are separate measures.
Why shot differential can be useful
Shot differential adds another layer to a matchup by showing whether a team generated more or fewer shots on goal than their opponents.
This can help answer questions such as:
- Is the team generally outshooting opponents?
- Is recent goal success being accompanied by positive shot volume?
- Is the team winning despite being outshot?
- Is it losing despite generating more shots?
- Has recent shot performance improved or declined?
Total shot differential
Total shot differential uses the cumulative shots for and against across the selected sample.
The formula is:
- Total shots for minus total shots against
This version is especially useful when comparing equal-size windows.
Shot differential per game
Shot differential per game adjusts for the number of games played.
It is calculated as:
- Total shot differential divided by games played
This makes comparisons easier when:
- Teams have played different numbers of games
- Home and road samples differ in size
- Rolling windows have different lengths
- Schedule-condition samples are unequal
Rolling shot differential
Rolling shot differential updates after each completed game.
For a fixed-size window such as last 10:
- The newest completed game enters
- The oldest game drops out
- Shots for are recalculated
- Shots against are recalculated
- Shot differential is updated
The window therefore follows the team continuously through the season.
Home and road shot differential
Home shot differential includes only home games. Likewise, road shot differential includes only road games.
Possible windows include:
- Last 5 home or road
- Last 10 home or road
- Last 20 home or road
- Season home or road
This allows recent home and away shot performance to be evaluated separately.
Shot differential and shootouts
Shootout attempts are not treated as standard shots on goal in NHL game statistics.
The deciding shootout goal may affect the official final score, but it does not add an ordinary shot on goal to the team’s shot total.
Shot differential and empty-net situations
Shots on goal recorded during empty-net situations remain part of the official game statistics and are included.
Incomplete rolling windows
Before a team has enough completed games, a full rolling window does not exist.
Before five games, last 5 is incomplete. Before 10 games, last 10 is incomplete. Before 20 games, last 20 is incomplete.
Neither games from the previous season nor preseason games are included. If partial samples are shown, they should be labelled clearly.
Official statistical corrections
Official shot totals may occasionally be corrected after a game. If the underlying game record changes, Daily Rink Form can recalculate affected statistics.
A correction may alter:
- Season shot differential
- Rolling shot differential
- Home and road splits
- Schedule-condition splits
- League rankings