Foundations

The Scrum core as patterns

A Scrum Book describes Scrum through two "pattern languages", one for the organization and the other for the value stream. It sums up the framework as a series of twelve patterns, to be put in place one after another. This article presents that overall map and the patterns that serve as a starting point: The Mist, Vision and Value Stream.

Where to begin

In a medium-sized town, volunteers from several charities have been talking for months about opening a community grocery, a store where people on low incomes can buy food at reduced prices. Each has their own idea: one is thinking of students, another of retirees, and a third mainly wants to stop unsold food from going to waste. One volunteer has heard about Scrum and suggests holding a Daily Scrum. The suggestion falls flat, because there is as yet no team, no goal and no work to replan each day.

This scene illustrates a central idea of the book: the elements of Scrum cannot be put in place in just any order. Each one assumes that others already exist, and the book proposes an order in which to build them.

Two languages for two constructions

A pattern describes a recurring problem, the forces in tension and a proven solution (see Scrum's patterns). A pattern language links these patterns together: for each one, it indicates which patterns it assumes and which ones complete it. The book contains two, because an organization that adopts Scrum builds two things.

The Product Organization Pattern Language describes the relationships between people: the roles, the teams and the regular meetings. It groups patterns 1 to 38.
The Value Stream Pattern Language describes the path the work follows, from the idea to the delivered product, with the artifacts and rhythms that mark it out. It groups patterns 39 to 94.

The authors justify this split by an observation: the patterns of one language depend heavily on one another, and only loosely on those of the other language. They acknowledge that the separation is "a bit artificial", since Scrum forms a whole, and they advise building the organization and the flow in parallel, one pattern at a time.

The four events that bring people together (Sprint Planning, Daily Scrum, Sprint Review and Sprint Retrospective) are numbered in the first language, whereas the Sprint, which structures time, belongs to the second. Each language is shown as a graph, in which a line connects a pattern to the ones that refine it.

Before the team: The Mist and Vision

The first language begins with a pattern with an unexpected name, The Mist (one star). Its context is that of the grocery: a vague longing shared across a community, and people each trying on their own to solve a great problem with the means of their own trade. For want of effective cooperation, they stop at local benefits.

The forces the pattern describes are historical. Innovation has flourished when people with varied skills could exchange freely, and on this point the authors cite Steven Johnson (Where Good Ideas Come From), who credits cities with being the cradle of innovation. Yet such communities have remained "beneath the shadow of hierarchy" and of conformity. The industrial revolution "saw the hands of many carrying out the designs of a few."

The solution is that one person, or a few people thinking together, create the conditions for the preparatory work from which teams can emerge. This work follows an emerging vision: to improve the quality of life of certain people through a product that adds value both for those who build it and for those who use it. The result is a group brought together by a common interest, which becomes conscious of a Vision.

The second language starts in the same place, with Vision (two stars, also called Product Vision). Its problem is a dilemma: "People thrive within constraints that channel their creativity and work towards a common good, but it's also true that overly specific constraints can turn contributors into subservient robots who blindly follow orders rather than following with their heart."

Several forces are added. Diversity of viewpoints is valuable, because it makes it less likely that the team will overlook a good idea, and it can also pull the team in several directions. A goal that is too vague scatters energy in low-value experiments, and a goal that is too narrow leaves avenues unexplored. A goal becomes shared only if the team has helped to shape it. Finally, "the future is inherently unknowable", and committing to a final result over a long time frame is fraught with danger.

The solution: "The individual who embodies the passion for this new product effort takes on the role of Product Owner, around whom stakeholders and potential future coworkers rally to articulate and together to define and refine a Vision." The Vision is the description of a desired future and of how the product contributes to it.

The pattern distinguishes two levels. The Vision in the broad sense gives a direction. The Product Vision is concrete and covers four considerations, which the authors take from Roman Pichler (Agile Product Management with Scrum, 2010): the key features of the product, who is going to use it, the customer needs it will address and how the vendor will benefit. A Vision can evolve, and a team sometimes discovers quickly that its own was off target.

From the mist to the Vision. The volunteers of the community grocery meet one Saturday. Nadia, who has run a food distribution for ten years and knows the families in the neighborhood best, agrees to lead the project. With her, the group formulates a Vision: "in our neighborhood, nobody goes without fresh food for lack of money". It then sets out the Product Vision by answering the four questions. The key features are a store where people choose their own products, at reduced prices, and a welcome where nobody has to justify themselves in front of other customers. The users are families referred by social workers and students on means-tested grants. The need is to be able to buy fruit, vegetables and dairy products. The charities benefit by no longer having to manage separate stocks. This Vision already rules out some ideas: home delivery, which one of the volunteers was arguing for, is not part of it for now.

Value Stream: organizing the path to the user

A Vision produces nothing by itself. The pattern Value Stream (two stars) starts from this problem: "The development process and the path from conception to market are as important to product success as the product idea itself." The forces have to do with complexity. The more elaborate a product, the more it requires teamwork and thoughtful coordination, and good processes and good people are not enough on their own. The solution: "The Product Owner creates an ecosystem whose elements build on each other to deliver ever-increasing value in an evolving product." At its center is a process that regularly delivers Increments of the product to the stakeholders.

In Scrum, value follows a known route: from the Vision to the Product Backlog, then to the Sprint Backlog and the Increment. Feedback from users flows back the other way to the Product Owner. The pattern also lays down a rule of organization: the development of a value stream is the job of a single Scrum Team, so as to eliminate handoffs between teams, which delay feedback and cause rework.

The twelve core patterns

The chapter of the book entitled The Scrum Core as Patterns reduces the framework to twelve patterns: the team, three roles, five events and three artifacts. The authors see in them "probably the minimal set of patterns which together could be called Scrum", and they present it as a typical sequence, in the order in which an organization would introduce it.

Order	Pattern	What it puts in place	Article in this corpus
1	Scrum Team	A complete team that operates as a small business within the organization	The Scrum Team
2	Product Owner	A single person accountable for the Vision and for value, who expresses them in the Product Backlog	The Product Owner
3	Development Team	The team that builds the product, Increment after Increment	The Developers
4	ScrumMaster	A guide to the process and to continuous improvement, serving the team	The Scrum Master
5	Product Backlog	The ordered list of what will be delivered, revised in every iteration	From Vision to Product Backlog
6	Sprint	A cycle of consistent length to plan, build, review and improve	The Sprint
7	Sprint Planning	The meeting of the whole team that prepares the work of the Sprint	Sprint Planning and the Sprint Backlog
8	Sprint Backlog	The Developers' work plan for reaching the Sprint Goal	Sprint Planning and the Sprint Backlog
9	Daily Scrum	The daily meeting where the Developers adjust that plan	The Daily Scrum
10	Sprint Review	The team's review of the product at the end of the Sprint	The Sprint Review
11	Regular Product Increment	A cohesive Increment, meeting the Definition of Done, which the Product Owner may make available	The Definition of Done and quality
12	Sprint Retrospective	The team's reflection on its way of working, with one improvement to carry out in the next Sprint	The retrospective and continuous improvement

This order has a logic. The first four patterns bring people together, the fifth gives them a list of work, and the next seven describe a Sprint from beginning to end. The book specifies that the sequence is an example and that you should trust your own judgment rather than follow it as an obligation. A team that has already started finds where it stands and begins from there: it first puts in place the broadest pattern it is missing, then moves on to the ones that refine it.

A team that was perfecting the wrong pattern. At a company that makes software for veterinary practices, a team of six has been working in two-week Sprints for a year. It devotes its improvement efforts to estimation, which it considers unreliable. Nothing helps: half the planned work changes in the middle of the Sprint. Looking at the sequence, the team realizes that a pattern right at the beginning is missing. Priorities come from three directors, each of whom sends requests straight to the Developers. So there is neither a Product Owner nor a single Product Backlog, and estimation is a much finer-grained pattern, which assumes a stable list. The company then gives the Product Owner role to the head of customer support, who knows the customers best, and the three directors now go through her. Two months later, changes in the middle of a Sprint have become rare, without the team having changed the way it estimates.

Where it differs from the 2020 Scrum Guide

This chapter of the book and the Guide describe the same elements, with a few differences.

The book counts three roles, and the Development Team is "a team within the Scrum Team". The 2020 Guide speaks of three accountabilities within a single team and states that "within a Scrum Team, there are no sub-teams or hierarchies."
The book has the work start from a Vision. The 2020 Guide does not use this word. It introduces the Product Goal, a goal for the product set out in the Product Backlog, which the team "must fulfill (or abandon)" before taking on the next one. The book's Vision is broader and more distant.
In the book, the Product Owner decides at the Sprint Review what goes into the coming release. The 2020 Guide specifies that "the Sprint Review should never be considered a gate to releasing value", and that an Increment may be delivered to stakeholders before the end of the Sprint.
The book asks that the Sprint Retrospective lead to one improvement to carry out in the next Sprint, as the 2017 edition of the Guide did. The 2020 edition says only that "the most impactful improvements are addressed as soon as possible."

Limits and pitfalls

The sequence of twelve patterns lends itself to a checklist reading, in which you check off twelve boxes before declaring yourself to be "doing Scrum". The book guards against this, since it places The Spirit of the Game before all the other patterns, but a presentation as a table invites that reading.

The Mist and Vision are written in an almost lyrical register, which speaks of quality of life and of breaking with "the servitude habits of past work practices". They name a real stage, the one where a project is still only a shared wish, without offering much to check. The visions the book cites, such as Bill Gates and Paul Allen's for Microsoft, are those of companies that succeeded, told after the fact.

A Vision can also remain a slogan. If it never helps to turn down a request, like home delivery in the grocery example, it is not doing its job.

Finally, nothing establishes that the proposed order is better than another, or that these twelve patterns are the necessary minimum. That is the authors' judgment, based on their experience (see Criticism and the state of the evidence).