Stream Drag Index

The primary users of Stream Drag Index (SDI) are the members of the Stream Team.

SDI can be aggregated to quantify the resistance experienced by one or more teams and can be used to rank or compare the effects of organizational drag across multiple teams.

The Stream Drag Index is calculated by multiplying the Story Drag Coefficient (SDC) by the Time Raised (TR), which is the time it took to resolve the impediment.

 

SDI = SDC x TR

 

The Story Drag Coefficient (SDC), just like its aerodynamic counterpart, the Drag Coefficient (CD), is a dimensionless quantity. CD is used in the drag equation to calculate the energy needed to move an object in a fluid. A lower drag coefficient indicates that the object will experience less aerodynamic or hydrodynamic drag. SDC represents the effects of organizational drag experienced by a work-item when it is being converted into an increment of work by an agile team.

SDC is a function of Impeded Story Points (ISP), Teams’ Capacity (TC), and Sprint length (SL).

 

SDC=ISP/(TCxSL)

 

Where, ISP stands for Impeded Story Points, and it is the sum of the user story points that are impacted by a given impediment. TC stands for Team Capacity and is the average sum of the team’s velocity over the last three Sprints, and SL stands for Sprint Length, and it is the number of business days within a Sprint.

If we inspect the average SDC values of teams, then we can use that metric to invest and empower in teams with higher SDC values. It is also important to note that a team that is doing great in one Agile Stream may not achieve similar results in a different one. In other words, SDC does not represent the team’s efficiency. SDC represents how much empowerment and support the team has to convert work-items into increment within the Agile Stream.

Once SDC is known, Stream Drag Index is calculated by multiplying SDC with Time Raised (TR). TR is the time the team first discovered the impediment, and not necessarily the time it was brought to the attention of the Scrum Master or Stream Team.

SDI is used extensively in the Daily Stream Meeting to rank and prioritize Stream Impediments as they are added into the Agile Stream Board. Multiple ranking strategies can be applied to sort the Agile Stream Board.

During a Sprint, each impediment will experience some resistance and that resistance will be captured in the Stream Drag Index. When we aggregate the SDIs of all impediments within a Sprint, then we get a representation of the organizational drag experienced by the agile team, and we call that Stream Drag (SD).