The variety of Agile frameworks can confuse even experienced development teams, especially when it comes to understanding the differences between them and choosing one for a specific project.
Today, we’d like to focus on the two particular Agile frameworks you may be considering – Extreme Programming vs Scrum. We are going to cover basic similarities and differences between them – so, it’ll be easier for you to wrap your head around their concepts and choose the one for your particular project (or you can even decide to combine them!).
What Scrum & XP Have in Common
Both Scrum and Extreme Programming are Agile frameworks – which means, they build on top of Agile principles, and provide clear guidelines for product development. (Remember, Agile itself is just a list of values).
Both of the frameworks divide the development process into sprints, have a planning meeting before the development starts and pinpoint user stories during it. Besides, they both imply having a planning meeting before each sprint as well. Their primary goals are similar as well: both Scrum and XP focus on delivering a high-quality product to the customer as fast as possible.
Scrum vs Extreme Programming: X Key Differences
Well, this is where all the similarities end. So, now let’s take a look at Scrum vs XP comparison and dive into X differences between Scrum and XP that matter the most.
This is actually the main difference between Scrum and Extreme Programming. Scrum is focused heavily on management itself – i.e. it deals with everything you do when you are not actually coding. Scrum determines how you plan and analyze your results, as well as how to increase productivity.
Extreme Programming is, in its turn, described as concentrating on the test-driven approach. Its principles are, basically, best engineering practices taken to the extreme (hence the name “Extreme Programming”). XP is often said to equal pair programming; however, it is not completely true. While XP does include this practice, it consists of 11 more practices, including writing unit tests first, continuous integration, etc.
A quick side note: if you decide to use the XP framework, make sure you follow all 12 guidelines – omitting even one of them may make the whole process inefficient.
While both frameworks use sprints as development stages (and you have to present the customer with a working system at the end of each sprint), their approach towards them is different, too.
Scrum sprints last for two-four weeks, and their length is quite flexible. Under XP, however, you have one week (sometimes two) to develop a working system – and it should be a 40-hour week to make sure developers don’t get exhausted.
What is also interesting, the aim of an XP sprint is not focused on product release – it is to create a working bug-free system. In turn, Scrum sprints are supposed to result in a working product.
Under XP, developers don’t make a new feature until it is needed. So, changes can be made by the customer during the sprint itself – and they are encouraged to be made in the early stages of development, of course.
In the case with Scrum, once the planning of the sprint is done, it is impossible to introduce changes during the sprint – so, the customer has to wait until its end to do this.
If an enterprise uses Scrum, all the communication with the product owner (i.e. the customer) during the development itself is done by the Scrum Master. The main part of it concerns prioritizing user stories for each sprint and making sure they are totally clear for developers.
In case you have chosen XP, the customer is the one who communicates with the team of developers. He or she prioritizes the user stories as well, asks to make changes and gives feedback on the results of the sprints. Besides, the customer has to be always available for communication.
When a company or a startup works according to Scrum, the Product Owner determines the priority of the development tasks within a sprint; however, developers determine the order of their actions themselves.
As for XP, there is no such flexibility – the customer decides on the order of tasks, and the team has to follow it without any deviation.
Last but not least, these two frameworks have some differences in values. Keep in mind that any Agile methodology is more than just rules, it is a philosophy that determines the approach to development.
Although they have two values in common (Courage and Respect), the other three are different. Scrum values include Openness, Focus, and Commitment, whereas XP cherishes Communication, Simplicity, and Feedback.
There is no universally best framework suitable for all cases - each of them has its pros, cons, and use cases. If you don't know how to settle on just one framework, what you can do is combine Scrum and XP - many companies already profit from using hybrid methodologies and integrate XP techniques into the Scrum/Kanban/Lean workflows, so you can be one of them.