Extreme Programming (XP) vs Scrum: A Comparison of Agile Methodologies

For the development of software products, the Agile methodology has over the years become a very popular choice for lots of businesses and organizations.

Since the origin of the methodology from the Agile Manifesto, it has brought about a mindset shift in the software industry with its prioritization of flexibility, adaptability, and collaboration in the development process.

As a result of the success of Agile methodology in software product development, lots of project managers and organizations have naturally gravitated towards it.

There are a lot of frameworks that use the Agile Methodology, and Extreme Programming (XP) and Scrum happen to be two of the most popular of them.

While XP and Scrum share similarities, there are key differences between them that come into play when you’re dealing with different projects and teams and you’re trying to decide which is best to use.

If you are weighing these options and looking for which is best suited for your project or organization, then this post is going to be helpful to you in deciding.

In the post, I’ll give you an overview of XP and Scrum, highlight their individual uniqueness, and an XP vs Scrum head-to-head comparison to provide insight on which might be right for your team.

What is Extreme Programming (XP)?

XP is an Agile methodology introduced in the late 1990s for software development that is designed to help teams deliver high-quality software quickly.

It consists of a set of practices that helps teams maintain focus and progress steadily by embracing simplicity, change, collaboration, communication, continuous integration, automated testing, and customer involvement.

One of the key principles of XP to ensure high-quality is customer involvement from initiating to closing in the development process.

It emphasizes the importance of writing tests before writing code and regular, small releases to get feedback from customers.

This way, the team is always working on features that are of utmost priority to the customer, and the final product is geared to the customer’s needs.

What is Scrum?

Scrum is a lightweight framework developed in the early 1990s that uses the Agile methodology to develop solutions to complex problems.

Just like XP, it was created to help teams deliver high-quality software quickly and efficiently.

The Scrum framework is designed to be as flexible and adaptable as possible, with an emphasis on teamwork, communication, and transparency.

Scrum consists of small cross-functional and self-managing teams made up of a Product Owner, Scrum Master, and Developers working on a Product Backlog to meet a Product Goal.

The Scrum team works in iterations or sprints which are short, time-boxed periods of work to create value incrementally.

Each sprint is designed to produce a working and usable version of the product based on features picked from the prioritized Product Backlog which forms a Sprint Backlog.

Going in-depth into the Scrum framework isn’t the focus of this post. However, this Scrum 101 tutorial will give you a concise guide on the Scrum framework.

XP vs Scrum: Understanding the Key Differences

Although XP and Scrum are both Agile methodologies and thus share many similarities, there are also some key differences between them that make them more suitable for different projects and teams.

Think of these differences as the different flavors of ice cream that make each have a unique taste. These are some important differences worth considering:

1. Practices

When it comes to practices, XP and Scrum differ in a sense in this regard. XP happens to have a more prescriptive set of engineering practices, including things like continuous integration and pair programming.

Scrum on the hand is flexible in practice and focuses on the key principles of Agile, like adaptability, flexibility, and collaboration.

2. Customer Role

Both methodologies believe in customer involvement in order to be able to deliver what’s actually valuable to the customer, rather than software with a ton of features that may not necessarily be needed.

However, in XP the customer is an active participant throughout the development process, while the customer is more of a passive participant in Scrum and provides input to the team through the Product Owner.

3. Sprints

For its development process, Scrum makes use of time-boxed iterations of 2 weeks to 1 month called sprints to divide the work to be done and develop the software iteratively and incrementally.

XP on the hand is focused on feedback as rapidly as possible. XP teams work in iterations typically 1 week or 2 weeks long.

4. Feature Prioritization

While XP and Scrum develop the software iteratively by prioritizing features, there’s a slight variation in the way both methodologies go about it.

For XP, the features are prioritized by the customer and the team works on them in that order strictly.

In Scrum, however, the Product Backlog is prioritized by the Product Owner. The Scrum team then selects features that they can finish within a sprint and work on them to deliver a Product Increment.

Unlike the XP team which strictly follows the prioritization order, the Scrum team can determine the sequence of developing the Backlog items.

5. Changes During Iterations

Changes are an integral part of the Agile methodology as a part of adaptation to feedback. However, different Agile methodologies manage these changes differently and XP and Scrum differ in this regard.

For XP, teams can make changes to items to be worked on during iterations so long they haven’t started working on the item.

Scrum on the other hand doesn’t allow changes to Backlog items during sprints. Once items have been picked during Sprint planning from the Product Backlog, the team is committed to delivering those items.

6. Ceremonies

The Scrum framework has 4 ceremonies or events enclosed in a container ceremony. The ceremonies are Sprint Planning, Daily Scrum, Sprint Review, and Sprint Retrospective.

These events are enclosed within a Sprint which is the container event and they form the core of the Scrum framework.

XP on the other hand doesn’t have any formal ceremonies within its iterations and the development process in general.

7. Collocation

Due to the need for the customers to be present and have input in the development life cycle, XP works best with collocated teams of developers and customers.

Scrum on the hand limits the customer’s participation to a passive role. Thus distributed teams can work easier in Scrum without having to rely on collocated teams.

Pros of Extreme Programming (XP)

Every project management methodology or approach has individual pros that make it suited for certain projects.

Some of the pros of XP include:

1. Flexibility

XP emphasizes a flexible approach to its development process which allows for changes in requirements and encourages customer involvement, leading to a better fit between the final product and the customer’s needs.

2. Emphasis on Collaboration

As a means towards a better-quality end product, XP emphasizes collaboration between developers, customers, and stakeholders.

3. Incremental Delivery

XP encourages frequent releases of small, working parts of the system, allowing for rapid feedback and faster delivery of value to the customer.

4. Automated Testing

XP emphasizes the importance of automated testing, leading to higher-quality software that is less prone to bugs.

5. Continuous Improvement

Continuous improvement is one of the principles of Agile methodology, and XP emphasizes this so as to encourage developers to regularly reflect on their processes and identify areas for improvement.

Cons of Extreme Programming (XP)

Some of the cons or limitations of XP include:

1. High Cost

Implementing XP requires a significant investment in technology and resources, and this can be expensive. The investment includes getting highly skilled developers and testers.

2. Cultural Resistance

While the Agile methodology revolves around change and adaptation, the truth is that achieving change in reality is difficult.

A lot of organizations and individuals are more comfortable doing things the way they always have even though they expect new results.

XP’s focus on collaboration and continuous improvement may be met with resistance in organizations with traditional hierarchical structures and a lack of trust in employees.

3. Collaboration Challenges

Xp requires a high level of collaboration between the developers, customers, and stakeholders.

This can be quite difficult to achieve in lots of teams and organizations due to inherent differences in human nature, and cultural varieties.

4. Challenges of Collocated Teams

While there are a lot of advantages to having collocated teams, it can also be a huge headache, especially in XP which thrives on rapid feedback and tight deadlines.

Getting everyone together can be difficult, especially the customers who may simply have no desire or time to participate in the development process.

5. Limited Scalability

Just like most Agile methodologies aside from SAFe, XP is best suited for small to medium-sized projects rather than large and complex ones with hundreds of developers.

In reality, every project won’t be small or medium-sized. And for large projects, adhering to XP practices becomes less feasible.

Pros of Scrum

Haven looked at some pros and cons of XP, and now we take a look at Scrum to have another perspective of both methodologies and how they stand side-by-side.

1. Defined Roles

One stand-out feature of Scrum is the clearly defined roles of Product Owner, Developers, and Scrum Master.

Each role is properly defined on the Scrum team and everyone knows their responsibilities to avoid a disconnect and things slipping through the cracks.

2. Incremental Delivery

Scrum encourages the delivery of small, working parts of the system, allowing for early feedback and faster delivery of value to the customer.

This way, a working product is available from the first sprint, and with each subsequent sprint, there is added features and functionality.

3. Flexibility

Just as with the XP framework, Scrum is designed to be as flexible as possible.

There’s ample opportunity for changes in requirements based on empirical knowledge gotten from every step of the development process.

4. Continuous Improvement

This is a by-product of Scrum’s flexibility and adaptation to feedback. By leveraging this feedback, processes and products experience continuous improvement for higher quality.

5. Transparency

Transparency is one of the pillars of Scrum. With the aid of the Scrum ceremonies, there is the provision of transparency in the development process, allowing all stakeholders to see the progress and status of the project at any time.

Cons of Scrum

Now we look at the other end of the spectrum which is the cons and limitations of Scrum framework.

1. Cultural Resistance

Scrum’s focus on collaboration and continuous improvement may be met with resistance in organizations with traditional hierarchical structures and a lack of trust in employees.

2. Intense Collaboration

Scrum requires a high degree of collaboration between the development team, stakeholders, and customers, which can be challenging to achieve in some organizations.

3. Limited Scalability

Scrum is designed for small to medium-sized projects, and may not be suitable for large, complex projects with hundreds of developers.

When to Use Extreme Programming (XP) or Scrum

If you’re going for a single framework for a project rather than a hybrid approach, you may be faced with a choice between XP and Scrum.

Both of these Agile methodologies have their strengths and weaknesses, and have projects that may be best aligned with one of these frameworks.

Projects that XP may be your go-to approach include projects that have a heavy technical component, as its emphasis on automated testing and continuous improvement can lead to higher-quality software.

For projects that require as much flexibility as possible and passive customer involvement, then it’s best you go for Scrum.

Can XP and Scrum be Used Together?

Yes, XP and Scrum can work together as a hybrid methodology, and is more common than you may realize.

While in theory, it sounds all good and fancy to stick to an Agile methodology and “keep it pure”, it doesn’t really work that way in reality.

If we’re keeping things real, the core of Agile is to be as flexible as possible within the methodology, so there’s no reason why any team or organization should be stuck to one approach.

What’s most important is that processes used follow the values and principles of Agile while harnessing the best parts of either framework.

Conclusion

Both XP and Scrum are great Agile methodologies, and the best choice for your team will depend on the specific needs of your project.

Ultimately, the most important thing is to choose a methodology that will work well for your team and your project.

It’s also worth noting that many teams use a hybrid approach, so you don’t necessarily have to pick one or the other.

By understanding how each works, you can take the best elements from both XP and Scrum to create a custom methodology that works for your project or team.