Comprehensive introduction to scrum

Scrum Summary

Scrum theory is based on a foreign discipline called Process dynamics, Modeling and Control. What does it mean? There are two methods of process control: predefined Process Control and empirical process control. The pre-defined process is to formulate a detailed plan before execution, and then strictly follow the plan. This control method is applicable when the process is relatively simple, however, if the process cannot be predicted in a very detailed manner, the pre-defined process will not be able to cope with the problem. At this time, "experience process control" is more suitable for process control.

Experience process control focuses on "check" and "adjustment", that is, the process is constantly checked for problems during execution and then adjusted according to the actual situation.

Both processes have their own advantages and disadvantages.

The pre-defined process is still widely used in today's software industry. Why? This is because the pre-defined process can provide a rough project budget and risk assessment before the project starts, so that investment talents can safely invest in projects. Of course, its disadvantage is that the risk of dealing with changes is very poor. Especially in the software development process, changes are inevitable and many situations are unpredictable, therefore, the predefined process is insufficient in this case.

Next, let's talk about how to use empirical process control for project management in scrum.

Typical waterfall projects generally involve project managers, team lead, developer, demand analysts, system architects, and testers. Usually testers, requirement analysts, and developers communicate in writing between different teams. This is a typical predefined development method.

Roles and responsibilities of scrum:

Scrum roles include team, scrum _ Master, and product owner.

Scrum _ Master: responsible for organizing team development, guiding and observing team, and correcting problems. Scrum _ master is not a project manager. It can only provide guidance for commands under the team. In addition, the scrum _ Master should prevent all factors other than the team from interfering with the Team's work. Therefore, the scrum _ Master is compared to a "Dog dog" to protect the herd and guide the direction of the herd.

Team: Responsible for requirement analysis and development. All work is organized by yourself.

Product owner: The product owner is responsible for proposing requirements and prioritizing requirements.

Principles of scrum:

1. "The Art of possible"

The art of possibility is a notable principle of scrum, which emphasizes that people should not focus on what they cannot do when thinking about things ", instead, we should focus on "what can be done or what can be done". We should not be troubled by many uncertainties. We can do what we can first, and then see what new discoveries we have, is there any new thinking. This is based entirely on empirical process control theory.

2. Self-organization

The team decides how to develop and solve the problem on its own, because no one knows their system better than the team itself.

In addition, this self-organizing team approach can increase the morale of the team and increase the sense of responsibility of the team members.

In addition, it turns development work into an interesting thing.

3. Communication

Scrum emphasizes communication. The team should be able to communicate face-to-face in a timely and effective manner at any time during their work, and oppose the internal document communication methods. All communication barriers should be removed.

For example, the compartment between traditional companies seriously hinders communication and should be removed.

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4. Daily visibility into the project

The basis of experience process control is to make the project transparent and problems emerge, because this allows inspection and adjustment.

Therefore, standing meetings are required every day for discussion.

In addition, velocity _ chart and burn up (down) chart are used to display the speed and project progress.

5. incremental product delivery

Based on the "Art of possible", scrum can complete the high-priority requirement in each iteration cycle, so that each iteration can be deliver business value. In this way, the customer can incrementally obtain available products, so as to further propose more practical and available requirements.

In fact, every iterative development can deliver business functions, but it is not particularly emphasized, but scrum strictly emphasizes this. Because it is a natural product based on empirical process theory.

Compared with the values of traditional development methods, scrum:

1. Iterative delivery allows customers to obtain available products before the project is completed, increasing customer satisfaction, the probability of project success, and the accuracy of subsequent requirements.

Especially the ability to resist changes is strong.

2. "Art of possible" allows the project to be started as soon as possible and to produce results quickly.

3. "Daily visibility" can effectively present project problems, which is conducive to timely solving problems.

4. Self-organization is conducive to boosting team morale and enabling people with the best understanding of the system to do the right thing.

All aspects of scrum:

1. Quick Start

There are few resources invested at the beginning of any project. For scrum, there are usually two to three people, including Dev and Ba, who can analyze the project and find the Master stories.

2. After the preliminary analysis, more Dev will be invested for development, and there will be a daily briefing. The value of the briefing is: Check and adjust, check whether the progress is consistent, whether there is a new problem, and then adjust the next step, instead of simply reporting to the scrum _ Master.

3. When Dev develops story, BA implements a new story card.

4. After the new card is completed, the customer will sort the priority based on business needs.

5. then Dev is organized to evaluate the workload of the story card, not in the unit of day, but in the point.

4. Most of the development processes use XP, and XP works well with scrum.

5. At the end of each iteration, products should be presented to the customer.

Scrum development method bidding for pricing Projects

1. The customer can stop the project at the end of any iteration and still get products that can be launched.

2. Scrum has a strong ability to resist changes. Before any iteration starts, the customer can modify the demand without paying for it, which has a great advantage in bidding the price contract.

Problems common to scrum during implementation

1. The implementation of scrum must be based on the company's corporate culture and be integrated with the corporate culture; otherwise, it is difficult to succeed.

2. No one can predict what will happen in the future, especially when the situation is unknown.

Therefore, when estimation is performed in each iteration, it is normal to predict inaccurate results, especially in the previous iterations.

3. in many cases, some infrastructure construction will be performed before the business functions start to be implemented. These work will account for a large proportion of the previous several iteration tasks and have a high priority. However, at the same time, business functions must also be released for each iteration,

Because the infrastructure requires actual business functions to verify its correctness.