Scrum, Crystal, Extreme Programming: Differences & Similarities

By Susan May

Agile, as a collection of methodologies, has revolutionized the product development world. It has brought in some fundamental changes in the way organizations work, allowing them to have more streamlined processes, adapt faster, be flexible, stay ahead of the competition and help retain customer trust. Successful organizations almost always are agile in their ways and have adopted some of the many popular frameworks that the Agile umbrella encompasses such as Scrum, Crystal, Extreme Programming and more. This blog is about the three most popular agile frameworks Scrum, Crystal and XP, their characteristics and their differences.What is Scrum?Scrum is a lightweight framework that helps people, teams and organizations generate value through adaptive solutions for complex problems—Scrum Guide Scrum is the most popular and widely used Agile methodology. It is a lightweight framework that helps teams and organizations address complex problems and adapt to changing requirements. It allows teams to adapt the processes to suit their project and organization needs. It can be tailored and yet ensures maximum productivity. Not only does it work well with small projects at the team level, but also delivers great results when scaled at the organizational level. Advantages of ScrumScrum is flexible, incremental and adaptable It reduces time to market It enhances creativity and innovation Scrum lowers development and operation costs It enhances quality of end product Scrum ensures customer satisfaction through quick feedback cycles Scrum helps implement continuous improvement It motivates and empowers teams How does Scrum work?You know you are doing the Heart of Scrum, if the team has a potentially shippable increment of product at the end of a sprint-- Jeff Sutherland Scrum uses an incremental and iterative approach to product development. It works by breaking up a large project into smaller chunks and building the product is built through phases. These small chunks are called sprints or iterations. Once the sprint length has been defined, based on the number of tasks that can be accomplished in each sprint, the length is fixed for all the successive sprints in the project. Sprints can be 2 to 3 weeks long and end with the delivery of a working feature of product. Scrum is based on the three pillars of empirical process control, which are transparency, inspection, & adaptation. Scrum teams are made up of three defined roles: Scrum Master Product Owner Developers Each team is generally made up of up to nine members who have varied skills. Scrum works because its teams are highly cross functional, self-organized and motivated. All team members work towards a single objective and that is to deliver the product goal. Team members live by the five values of Scrum that are: Commitment, Focus, Openness, Respect, and Courage. Working on these values helps team members work as a cohesive unit to minimize risk, deliver quality products and ensure customer satisfaction. Scrum employs quick feedback cycles and this helps teams to work on implementing customer feedback, thus making it extremely flexible and responsive. What is the XP methodology? XP too, like Scrum, is an Agile methodology that focuses on helping teams develop high quality products and adapt to changing requirements. This facet of XP makes it very apt for modern product development where customer requirements can change at the drop of a hat and developers and teams need to be able to immediately incorporate changes into the product design before it is shipped. Extreme Programming (XP) is an agile software development framework that aims to produce higher quality software, and higher quality of life for the development team. XP is the most specific of the agile frameworks regarding appropriate engineering practices for software development—Agile Alliance Advantages of XPProductivity and delivery are measurable Is simple to use Reduces risks related to programming and project failure Helps ensure customer requirements are incorporated Ensures constant feedback to improve products Speeds up creation of working software Prevents accumulation of work and leads to happier and more focused teams How does XP work?XP defines a very specific set of engineering practices, as the basic premise of XP is taking good practices to an extreme. There is a lot of emphasis on the technical aspects of software development, as the philosophy of XP is that following good engineering practices allows teams to ensure that high quality code is delivered at an incremental pace. XP, like Scrum is also built upon values and practices. XP values are: Communication, Simplicity, Feedback, Courage, and Respect The practices of XP are interconnected and help teams minimize risk and ensure better quality output. The Planning Game Small Releases Metaphor Simple Design Testing Refactoring Pair Programming Collective Ownership Continuous Integration 40-hour week On-site Customer Coding Standard The key roles associated with XP teams are: Customer Programmers Coach Tracker CrystalCrystal is a more flexible Agile methodology and was developed by Alister Cockburn for IBM in the early 1990s. It is in fact a family of methodologies and was developed even before the creation of the Agile Manifesto. As it involves the use of many practices used by Agile, it is now classified as an Agile methodology. Crystal is not a one size fits all methodology. It can be tweaked based on the project and the team members. Since the methodology is often directed by the team itself, it works better when implemented by seasoned developers. Crystal is primarily based on these properties: Teamwork Communication Simplicity Responding correctly Reasoning Reconstruction Frequent adjustments Process improvements Crystal is broken into different coloured groups such as Clear, Yellow, Orange, Red and more. Based on the complexity of the project and the process and practices to be applied to it, the type of Crystal method to be applied can be chosen. The type of colour to be used depends on: The team sizes Criticality Priority of the project SCRUM vs XP vs CrystalFeaturesScrumXPCrystalApplicationCan be applied to any project that can benefit with an iterative and incremental product development cycleApplies more to programming projectsCan be applied to any projectUsageHas to be implemented in its entiretyCan be tweaked to suit the needs of the projectCan be tweaked based on the type of project being implementedRolesProduct Owner Scrum Master Developers Customer Programmers Coach Tracker Executive Sponsor Executive Lead Designer Programmer The Ambassador User Tester Project Manager Business Expert IterationsTypically, 2 to 4 weeks in lengthTypically, 1 to 2 weeks in lengthTypically, 1 week. Cannot be more than 4 monthsChanges accepted in iterationsOnce an iteration is completed, no changes can be madeChanges are allowed during and even after the sprint is ordered to provide better featuresOnce the process and budget are finalizedTask prioritizationPrioritization can be decided on by the team base on what will be most beneficial to the customerThe customer decides the priority of tasks and not the team. The team must develop tasks based on the priority stated by the customerPriorities are fixed as per criticality of tasksEngineering practicesScrum does not prescribe any set engineering methods. The focus is more on productivitySoftware engineering practices like pair programming, ten-minute build, test first programming etc are given more emphasisCrystal does not prescribe any set engineering methods. It is a combination of several Agile methodologies.Owner of the productThe Product Owner owns the product and defines and orders the product backlog itemsThe customer owns the product and sets the priority of stories for iterationsThe user owns the productMeetingsScrum meetings are arranged and run by Scrum MasterThe customer drives XP meetingsThe project manager or Coordinator takes down important points discussed during review meetingsIs there anything common between XP and Scrum?Both XP and Scrum are agile frameworks that have their own set of practices and processes that are geared towards helping teams perform to the best of their abilities and deliver value to the customers. While at their core they may differ in processes and practices, at the surface they are similar and build upon the values and principles of agile.Both use short sprints or iterations to deliver features incrementally and iteratively. They also focus on ensuring that customer requirements are implemented on priority through their quick feedback cycles. They both go through initial planning stages and have retrospective meetings to look back and see what can be improved. Many projects use both Scrum and XP practices to take the best of both and deliver the highest possible value to the customer.How is Crystal different from Scrum and XP?Crystal like Scrum and XP is an agile framework. It allows a lot of flexibility to teams and encourages teams to adapt the framework as per their need. The key principles of Crystal are: Frequent delivery Reflective improvement Osmotic communication Personal safety Focus on work Access to subject matter experts and users Technical tooling Conclusion Scrum and XP are great for projects that are intensive and prone to changing requirements. These two practices that have their foundations in Agile are focused on delivering value to the customer and hence most suited for modern projects that need to have quick, value focused deliveries. Which methodology you choose depends on the nature of your project and your team. Teams that are well versed with Scrum also choose to adopt the best practices of XP and Crystal to deliver maximum value.

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Scrum, Crystal, Extreme Programming: Differences & Similarities

By Susan May 05th Oct, 2021

Susan May

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Category: Blog
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6158 634 05th Oct, 2021

Scrum, Crystal, Extreme Programming: Differences & Similarities

What is Scrum?

Scrum is a lightweight framework that helps people, teams and organizations generate value through adaptive solutions for complex problems—Scrum Guide

Scrum is the most popular and widely used Agile methodology. It is a lightweight framework that helps teams and organizations address complex problems and adapt to changing requirements. It allows teams to adapt the processes to suit their project and organization needs. It can be tailored and yet ensures maximum productivity. Not only does it work well with small projects at the team level, but also delivers great results when scaled at the organizational level.

Advantages of Scrum

Scrum is flexible, incremental and adaptable
It reduces time to market
It enhances creativity and innovation
Scrum lowers development and operation costs
It enhances quality of end product
Scrum ensures customer satisfaction through quick feedback cycles
Scrum helps implement continuous improvement
It motivates and empowers teams

How does Scrum work?

You know you are doing the Heart of Scrum, if the team has a potentially shippable increment of product at the end of a sprint-- Jeff Sutherland

Scrum uses an incremental and iterative approach to product development. It works by breaking up a large project into smaller chunks and building the product is built through phases. These small chunks are called sprints or iterations. Once the sprint length has been defined, based on the number of tasks that can be accomplished in each sprint, the length is fixed for all the successive sprints in the project. Sprints can be 2 to 3 weeks long and end with the delivery of a working feature of product.

Scrum is based on the three pillars of empirical process control, which are transparency, inspection, & adaptation.

Scrum teams are made up of three defined roles:

Each team is generally made up of up to nine members who have varied skills. Scrum works because its teams are highly cross functional, self-organized and motivated. All team members work towards a single objective and that is to deliver the product goal. Team members live by the five values of Scrum that are:

Commitment, Focus, Openness, Respect, and Courage.

Working on these values helps team members work as a cohesive unit to minimize risk, deliver quality products and ensure customer satisfaction. Scrum employs quick feedback cycles and this helps teams to work on implementing customer feedback, thus making it extremely flexible and responsive.

What is the XP methodology?

XP too, like Scrum, is an Agile methodology that focuses on helping teams develop high quality products and adapt to changing requirements. This facet of XP makes it very apt for modern product development where customer requirements can change at the drop of a hat and developers and teams need to be able to immediately incorporate changes into the product design before it is shipped.

Extreme Programming (XP) is an agile software development framework that aims to produce higher quality software, and higher quality of life for the development team. XP is the most specific of the agile frameworks regarding appropriate engineering practices for software development—Agile Alliance

Advantages of XP

Productivity and delivery are measurable
Is simple to use
Reduces risks related to programming and project failure
Helps ensure customer requirements are incorporated
Ensures constant feedback to improve products
Speeds up creation of working software
Prevents accumulation of work and leads to happier and more focused teams

How does XP work?

XP defines a very specific set of engineering practices, as the basic premise of XP is taking good practices to an extreme. There is a lot of emphasis on the technical aspects of software development, as the philosophy of XP is that following good engineering practices allows teams to ensure that high quality code is delivered at an incremental pace.

XP, like Scrum is also built upon values and practices. XP values are:

Communication, Simplicity, Feedback, Courage, and Respect

The practices of XP are interconnected and help teams minimize risk and ensure better quality output.

The Planning Game
Small Releases
Metaphor
Simple Design
Testing
Refactoring
Pair Programming
Collective Ownership
Continuous Integration
40-hour week
On-site Customer
Coding Standard

The key roles associated with XP teams are:

Customer
Programmers
Coach
Tracker

Crystal

Crystal is a more flexible Agile methodology and was developed by Alister Cockburn for IBM in the early 1990s. It is in fact a family of methodologies and was developed even before the creation of the Agile Manifesto. As it involves the use of many practices used by Agile, it is now classified as an Agile methodology.

Crystal is not a one size fits all methodology. It can be tweaked based on the project and the team members. Since the methodology is often directed by the team itself, it works better when implemented by seasoned developers. Crystal is primarily based on these properties:

Teamwork
Communication
Simplicity
Responding correctly
Reasoning
Reconstruction
Frequent adjustments
Process improvements

Crystal is broken into different coloured groups such as Clear, Yellow, Orange, Red and more. Based on the complexity of the project and the process and practices to be applied to it, the type of Crystal method to be applied can be chosen. The type of colour to be used depends on:

The team sizes
Criticality
Priority of the project

SCRUM vs XP vs Crystal

Features	Scrum	XP	Crystal
Application	Can be applied to any project that can benefit with an iterative and incremental product development cycle	Applies more to programming projects	Can be applied to any project
Usage	Has to be implemented in its entirety	Can be tweaked to suit the needs of the project	Can be tweaked based on the type of project being implemented
Roles	Product Owner Scrum Master Developers	Customer Programmers Coach Tracker	Executive Sponsor Executive Lead Designer Programmer The Ambassador User Tester Project Manager Business Expert
Iterations	Typically, 2 to 4 weeks in length	Typically, 1 to 2 weeks in length	Typically, 1 week. Cannot be more than 4 months
Changes accepted in iterations	Once an iteration is completed, no changes can be made	Changes are allowed during and even after the sprint is ordered to provide better features	Once the process and budget are finalized
Task prioritization	Prioritization can be decided on by the team base on what will be most beneficial to the customer	The customer decides the priority of tasks and not the team. The team must develop tasks based on the priority stated by the customer	Priorities are fixed as per criticality of tasks
Engineering practices	Scrum does not prescribe any set engineering methods. The focus is more on productivity	Software engineering practices like pair programming, ten-minute build, test first programming etc are given more emphasis	Crystal does not prescribe any set engineering methods. It is a combination of several Agile methodologies.
Owner of the product	The Product Owner owns the product and defines and orders the product backlog items	The customer owns the product and sets the priority of stories for iterations	The user owns the product
Meetings	Scrum meetings are arranged and run by Scrum Master	The customer drives XP meetings	The project manager or Coordinator takes down important points discussed during review meetings

Is there anything common between XP and Scrum?

Both XP and Scrum are agile frameworks that have their own set of practices and processes that are geared towards helping teams perform to the best of their abilities and deliver value to the customers. While at their core they may differ in processes and practices, at the surface they are similar and build upon the values and principles of agile.

Both use short sprints or iterations to deliver features incrementally and iteratively. They also focus on ensuring that customer requirements are implemented on priority through their quick feedback cycles. They both go through initial planning stages and have retrospective meetings to look back and see what can be improved. Many projects use both Scrum and XP practices to take the best of both and deliver the highest possible value to the customer.

How is Crystal different from Scrum and XP?

Crystal like Scrum and XP is an agile framework. It allows a lot of flexibility to teams and encourages teams to adapt the framework as per their need. The key principles of Crystal are:

Frequent delivery
Reflective improvement
Osmotic communication
Personal safety
Focus on work
Access to subject matter experts and users
Technical tooling

Conclusion

Scrum and XP are great for projects that are intensive and prone to changing requirements. These two practices that have their foundations in Agile are focused on delivering value to the customer and hence most suited for modern projects that need to have quick, value focused deliveries. Which methodology you choose depends on the nature of your project and your team. Teams that are well versed with Scrum also choose to adopt the best practices of XP and Crystal to deliver maximum value.

Agile

Susan May

Writer, Developer, Explorer

Susan is a gamer, internet scholar and an entrepreneur, specialising in Big Data, Hadoop, Web Development and many other technologies. She is the author of several articles published on Zeolearn and KnowledgeHut blogs. She has gained a lot of experience by working as a freelancer and is now working as a trainer. As a developer, she has spoken at various international tech conferences around the globe about Big Data.