Earlier this year, Rushil Ram, Mike Gallimore, and Prashanth Iyer launched Tape to Tape, an online tracking system that can be used to record locations of shot assists, zone exits, and zone entries. Rushil and I will be running the Tape to Tape Project in order to compile a database of these statistics with the application Rushil created. We have already had close to 30 trackers sign up from an announcement on Twitter last week.

 

 

 

Each individual will track zone exits, zone entries, and shot assists for games they sign up for. Once the games are complete, the data will be exported to a public Dropbox folder. The goal with this project is to enhance our understanding of these microstats as they pertain to coaching decisions, player performance, and wins. What follows next is a description of what we will be tracking, a brief summary of the research that describes why these specific microstats are important, and how we will be tracking these events.

Zone Exits

Our current understanding of zone exits is that controlled zone exits may result in a better shot differential at the team-level. Alex Novet took it a step further with his talk at the 2017 RIT Hockey Analytics Conference, identifying that controlled exits lead to zone entries, center-lane exits are best for maintaining possession, and forechecking pressure has a significant impact on the type of zone exit.

Within the Tape to Tape tracker, zone exits will be tracked as follows:

• Pass – A completed pass to a player as he crosses (<2 strides) the defensive zone blue line or a completed pass that crosses the defensive zone blue line to a player in the neutral zone
• Controlled – A player successfully carries (2 or more strides) the puck across the defensive zone blue line into the neutral zone
• Uncontrolled – A player dumps the puck out of the zone with no clear intention to pass to a specific player or an exit pass fails to connect, resulting in the loose puck careening out of the defensive zone.
  • Lost – The team that dumps the puck out does not recover and maintain possession of the puck
  • Recovered – The team that dumps the puck out becomes the first team to establish clear possession of the loose puck
• Failed – An exit that does not result in the puck leaving the zone or an icing

Exits at even strength and the penalty kill will be tracked using these definitions.

A gray area that occurs is when a team enters their own zone on their own, or an opponent’s uncontrolled exit enters the zone. You will often see this on neutral zone faceoffs or small little regroups at even strength. The line we will draw for this case is that if the player is forced below the faceoff dots, an exit attempt will occur. If not, no exit attempt will occur.

So this faceoff will not lead to an exit attempt:

And this faceoff will lead to an exit attempt:

Finally, a team that exits the zone after the other team dumps the puck in and starts a line change will not have an exit attempt recorded.

Zone Entries

Most of the early work on zone entries was done by Eric Tulsky and colleagues as they worked to define how shot production is impacted by entry type. Later, Tulsky and colleagues had their paper on zone performance scores accepted at the 2013 Sloan Sports Conference. Since that time, there has been an explosion of zone entry work done by Corey Sznajder, Charlie O’Connor, Jen Lute Costella, garik16, Alex Novet, and many more.

From a special teams’ perspective, Arik Parnass defined which types of entries lead to more unblocked shots on the powerplay.

Within Tape to Tape, zone entries will be tracked as follows:

• Controlled – a pass or carry that results in a team maintaining possession for at least 2 strides into the offensive zone
• Uncontrolled – A dump-in or failed pass attempt/carry that results in the puck crossing the blue line without maintaining full possession of the puck for at least 2 strides
  • Lost – The team that enters the zone does not recover and maintain possession of the puck prior to an exit attempt by the defensive team
  • Recovered – The team that enters the zone recovers the puck prior to an exit attempt by the defensive team
• Failed – an entry attempt that does not result in the puck entering the offensive zone or goes offsides or a neutral zone dump-in that results in an icing.
• Tip-in – a player passes the puck to a teammate who never gains control of the puck, but tips it into the offensive zone.  Tip-in entries shall be tracked by the location where the puck was tipped in, with a setup pass added from the location of the passer
  • Lost – The team that enters the zone does not recover and maintain possession of the puck prior to an exit attempt by the defensive team
  • Recovered – The team that enters the zone recovers the puck prior to an exit attempt by the defensive team

All entries (even strength, powerplay, penalty kill) will be tracked using these definitions.

When a player fails an entry by trying to connect with a player close to the red line, but turns the puck over, the failed entry is on the passer, and the location recorded will be where the passer was as well.

If a team dumps the puck in and all 3 forwards go off for a change, an uncontrolled entry attempt will not be recorded.

What is and what is not a forechecking entry?

So this will no doubt be a difficult one to understand. All of the other events are widely known, and have been featured in analysis before. Forechecking is something that is getting added at the last minute. It stemmed from a conversation about when a team enters their own zone, but an opponent forces a turnover. This is the solution to a zone exit gray area.

Understanding what an exit attempt is will be the most important part. If there was no entry prior to the event, we will use the arbitrary line mentioned above in the exits section. If there was an entry, the question to ask is, was there an exit attempt occuring? If a player is moving up ice with control of the puck, or attempts to dump or pass the puck forward, this is an exit attempt. A turnover would result in a failed entry. In the case of the play below, although DeBrusk is moving up ice with control of the puck, he losses possession, forcing him to go back and retrieve the puck, canceling the exit attempt. When Bozak retrieves the loose puck, it is a forechecking entry.

Shot Assists

Ryan Stimson’s Passing Project allowed us to quantify the importance of shot assists in predicting future point production. Since that time, loserpoints has worked on a method to estimate shot assists and I’ve described the importance of Royal Road passes on the powerplay .

Within Tape to Tape, shot assists will be tracked as follows:

Trackers will record the location of each pass (max of 5) that precedes an unblocked shot (missed shots, shots on goal, goals). Passes will only be recorded if the pass was intentional and received successfully. A fumbled or incomplete pass will reset the passing sequence.

All shot assists (even strength, powerplay, penalty kill) will be tracked using this definition.

Linked Events

We will link events that occur within a reasonable time span of each other and that are logically linked together in the flow of the game. For example, an exit occured at 18:57, and entry occured at 18:55, and a shot occured at 18:53. The shot is linked to the entry and exit, and the entry is linked to the exit.  However, if a team exits the zone, loses possession in the neutral zone for several seconds, then eventually wins back possession and enters the zone, the entry and exit are not linked together.

How to get involved

The first thing you can do, is spread the word. Even if you yourself don’t have time or a means to track, someone you may know can. If you are interested in helping out with the project, and have nhl.tv or a similar service, you can fill out this form here.

We have already received outstanding support. This is a terrific way for people to get involved in hockey analytics. Three of our current writers here at Hockey Graphs (including myself) started by tracking shot assists for Ryan Stimson’s Passing Project. We hope this project can contribute just as much to the community, if not more.