Barnacles attach to ships and add drag

Barnacles attach to ships and add drag

In earlier entries of the Daily Process Thoughts, I believe we have established that basic Scrum process can be defined using three roles, five events and three artifacts. This is the Scrum canon, much like the canon of stories that make up the Sherlock Holmes series. Many organizations and consultants have added practices to Scrum in order to meet specific needs (if those needs are real or perceived is an open question).  At the Scrum Gathering in Las Vegas in 2013, Dr. Alistair Cockburn called these additions barnacles; Ken Schwaber has written extensively about “Scrum buts. . .” and “Scrum ands. . .”. Barnacles grow on the hull of ships and create drag, slowing the ship or requiring greater energy to drive the same distance. However for all of the downsides of a barnacles they serve a purpose, deliver a benefit, or they would not exist in nature.  The additions to Scrum must compete and deliver value or they will be swept aside.  Several of the more common barnacles are related to defining and estimating work. They include:

  • User Stories, phrased in the now classic “persona, goal, benefit” format, are an addition to the canon of Scrum.  User stories provide a disciplined framework for describing units of work, which improves communication.
  • Story Cards, which generally include the user story, acceptance criteria, size and other ancillary pieces of information, provide a means to the organize units of work a team will be working on.  Organization of information provides a means of visualizing gaps and keeping track of work items so they can be communicated (and in my case, so they don’t get lost).
  • Story Points, are a representation of the size of a user story or any unit of work based on the collective understanding of the team that is being tasked to deliver the work.  The use of story points provides a team with a consistent scale that helps team members communicate about their perception of size.
  • Planning poker, a variant of the Delphi estimation process, acts as mechanism to structure the discussion of size and estimation within Agile teams to increase communication, ensure all relevant voices are heard and to control paralysis by filibuster.

Add to the potential additions technical practices like Test Driven Development, Behavior Driven Development, Continuous Builds and hybrids like Scrumban and the number of potential barnacles can grow quite large.  That is the nature of a framework.  Techniques, practices and processes are bolted on to the framework first to see if they improve performance.  As practitioners and methodologists we must insure that only those that provide tangible, demonstrable value are allowed to stay bolted.  Remember that each organization and team may require more or less barnacles to be effective.  Like the Sherlock Holmes stories, others have extended the canon with their own stories, practices and process.  Some are valuable and find traction, while others are experiments that have run their course.

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