Por: Rodrigo Aquino     4017 visualizações     Tempo leitura: 11 min

Introduction

Scrum is an iterative and incremental development process and was initially created for managing software projects. Many of its features can be related to the lean principles and tools. Understanding this relationship is a way to know more clearly how to generate customer value, align software development with the company's strategy, reduce waste, etc.

In 1993 Jeff Sutherland, John and Jeff McKenna Scumniotales created the Scrum based on the Article by Takeuchi and Nonaka, "The New Product Development Game", published in 1986 by Harvard Business Review magazine. By 1995, Ken Schwaber had formalized the definition and helped to divulge the process around the world, especially in the software development area.

Different from model cascade that promotes only one delivery at the end of the project, a major feature of Scrum is to provide various customer deliveries during the entire designing of the software. With several deliveries we get more customer feedback and consequently constant learning the development team through small PDCA cycles.

Scrum Overview

The following figure shows all the stages and interactions between those involved in the process:

The Scrum framework - adapted from the source: http://vdschoot.com/agile/scrum/

Once the stakeholders (responsible for the product of the client) define generally what should be developed, the Product Owner (PO - who represents the client in the company that will develop the product) has the function to prioritize deliverables and plan the Product Backlog (a set of items to be worked on form the product). The Scrum Master (team leader), the team and the PO has a meeting to plan the Sprint (small functional delivery of the product), ie tasks which will have priority in development, and when they will be delivered (usually between 2 and 4 weeks). During the software development daily meetings take place, artifacts are updated and during the Sprint delivery there is a meeting to review what has been developed and consequently delivered to the customer. Customers receive what was agreed upon (part of software working) and at the end of the cycle there is another meeting only in the team about what was learned during that Sprint.

The roles of Scrum

• Product Owner (PO): represents the client in the company where the product will be developed. This single person will be responsible for developing and keeping the Product Backlog, to define priorities in the development, and negotiate possible adjustments in the product. From the lean point of view: due to the extreme difficulty in having a customer who will use the software or product within the company, with Scrum, to elect one representative in order to narrow the path of information to the developers. This is a way to reduce the risk of redoing that may appear during the product design. One of the concepts used in lean thinking is Genchi Genbutsu ("Go see"). In other words, the PO must know the customer well and ensure that the development team is working on the correct product feature. In addition, the PO must be in constant contact with the customer and always updated regarding to the job market in order to predict future adjustments in the product.
• Scrum Master (SM): is the leader in the development team and establishes the relationship between the developers and the PO. Some of their features are: to remove any impediments that hinder the team's progress, for example, internal disagreements among members of the team, involve infrastructure department in case some hardware is not working, etc. From the lean point of view: people are the key to the success of an organization, which is why they should be treated with respect at all times. A leader must be in constant contact with his team in order to know them well to understand deeply the problems that each member is passing day by day, so that he can help them and facilitate with the workflow and thus customer satisfaction.
• Scrum team: are those who develop the product and ensure quality. Although they have a leader, the team should be self-manageable and multifunctional. They are responsible the customer delivery for estimating. In many literatures you will find that the number of people to make a team should be 5-9 members. Jeff Sutherland, in his presentation at last Lean IT Summit held in Paris (October / 2014) reported that, from personal experience, an ideal team should be made up of 5 people. From the lean point of view: having multifunctional teams is a way to allow a quick flow of information, because a single person can do different tasks avoiding the delay for the availability of another team member. Regarding the number of people on staff, instructors of Lean Institute Brazil has been training people for over 16 years and, from experience, do not recommend groups greater than 7 people in activities (eg teams that make VSM) due to performance drop.

The Meetings of Scrum

• Sprint planning meeting (8 hours duration): Scrum Master, the team and the PO participate in this meeting in which the goal is to plan the delivery of Sprint (functional delivery of a piece of software). The PO defines the goal, and the priority items in the backlog that will form the Sprint. At this meeting the team divides in another Sprint backlog and makes estimates playing Planning Poker (it is a card game in which each card contains a Fibonacci sequence number to indicate the points each story or task take to develop. Each member chooses a card with the number that best indicates the amount of effort they will make to develop. Sometimes it is necessary to play a few rounds to get the amount of points with greater repetition by the team. Important: Never take the average of the cards, but choose one that most frequency appeared as an estimate). From the lean point of view: meetings are a waste of the process. Therefore, the Scrum Master should make sure that everyone is making the fullest in order not to lose focus with a concern to always generate customer value. Another parity with the lean philosophy is from the estimates (Planning Poker), ie no one is better an estimating how much effort (*) would be spent to develop something than the team itself. This form of estimation uses the same concept of Gemba, as mentioned before, therefore, we conclude that the chance of error is smaller.
  * Normally this is estimated not only in time but also in number of points.
• Daily meeting (15 minutes duration): This meeting is held at the beginning of work and involves the whole team besides the Scrum Master. All members stand and answer the following questions: What I did yesterday, what I will do today and what problems prevents me from continuing the work. From the lean point of view: In the book Toyota Product Development System, launched in 2008 by James Morgan and Jeffrey Liker, you can find quick and frequent meetings, which in this context serve to certify the leader if the project is being done as planned. It ensures that potential problems can be found quickly ready to be solved. We recommend using split times to help limit the duration of the meeting, this will make the team organize better in order that the time limit is not exceeded (for example to set a limit of 13 or 14 minutes).
• Review of Sprint (up to 4 hours): Participants in the meeting are the SM, the team and the PO in which the purpose is to deliver a part of the product working. If necessary, others involved in the project such as the client can also participate. From the lean point of view: A checklist should be managed by the PO in order to make sure everything was done according to the clients needs. A term known in the lean thinking is (complete and correct) that means: making sure that the information is complete and correct going any further (this procedure should be done during this meeting).
• The Sprint Retrospective (up to 3 hours): occurs between the SM and the team with the object to evaluate what happened during product development specifically during this phase. In other words, to discuss the pros and cons in order to enhance learning and improvement in future. From the lean point of view: the term used for this activity is called nemawashi, which literally means reflection. The Kaizen spirit should be part of the team and the thought must be: "today better than yesterday, tomorrow better than today".

Scrum artifacts

• Product backlog: it is a collection of stories (User Story - US) that describe what should the product contain. Each User Story can contain one or more features to be delivered to the customer. From the lean point of view: this can be considered as stock information (inventory is a waste categorized by Taiichi Ohno). For this reason we need to focus on reducing the backlog in order to work as close as possible to the third lean principle: the continuous flow. As the changes in a system can also be caused due to market demands (for example, adjustments to the client's business according to changes in law), the lesser the information in the stock, the lower the risk of rework and incorrect prioritization.
• Sprint Backlog: is a specific list of tasks that team has to do, to deliver part of the product to the customer. In this context one US can turn into one or more tasks. From the lean point of view: dividing the US into smaller tasks will make it easier to find the solution and expose problems. Lean is to expose problems and to find the root cause and share this knowledge with other company employees.
• Burndown chart is a graph report that we use to verify the progress of team work. It represents the number of points x amount of hours, also allowing you to compare the planned achieved. This graph should be updated daily so that decisions are taken in relation to what is out of schedule. There is also a frame called Task Board that shares and shows clearly what each team is developing in relation to its tasks. From the lean point of view: one of the lessons treated at Lean Thinking is to make the work of the people more visual possible. This type of management will help to create mechanisms proof of errors known as poka yoke, thus, we will try to get as close as possible to quality at the source, ie, preventing future errors going further.

Conclusion

Understanding the relationships of Scrum with lean it is important to identify the right of terms search in literature in order to deepen our knowledge on the subject. When some doubts arise during a project using Scrum, the lean thinking will certainly be a great ally in directing what to do in situations that are not yet documented.

It is true that the Scrum development process is helping many companies around the world to eliminate wastages during the conception of various types of products, mainly software. Scrum provides many advantages for those who use it and its great success is maybe because it creates an environment to value people, motivating them in their daily work. Valuing people, by the way, is a key feature of the lean thinking.

Bibliography

Data da publicação: 04/17/2015

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