Do Extreme Programming Folks Care about Scrum?

In a raging discussion on the Extreme Programming group Michael James started a discussion on whether Scrum is alienating Extreme Programming folks. He suggested that till date he had thought that XP and Scrum were allies but some members of the group had different thoughts.

Simon Jones suggested that though he is not anti Scrum but there are a few questions that spring up

- I do struggle to see what one gains from Scrum (apart from more effective marketing) that is not readily provided for in XP?
- Scrum feels like a project management related subset of XP.
- I've never been sure why Scrum /intentionally/ avoids detailed recommendations on engineering practices.
- A little knowledge can be a dangerous thing. Scrum either seems to give enough guidance to be more agile... or enough rope to hang yourself with.

Some members in the group who were supporting Scrum suggested that many XP ideas were actually based on Scrum since Scrum predates XP.

Seyit Caglar Abbasoglu sparked the discussion with his thoughts, he mentioned

I believe those engineering practices are the main part of XP that fears aged managers. It seems like Scrum guys are hiding them until they have the opportunity to show why they are needed and how they are useful. I'd not be surprised that some of those practices to be added into Scrum after they become industry standards.

Alistair Cockburn said that comments like these are alienating the Scrum folks. He added that practices of XP though "useful" are not "necessary" for a project to succeed. Other members countered that they had been on projects where Scrum was being followed without XP and eventually they had to introduce XP practices to make the project succeed. To this Alistair responded by citing example of a company where Scrum was being used without XP and the project was successful with happy customers. He also mentioned another project where Crystal was being used without XP and the result was positive.

Alistair further reiterated that he considered the XP practices useful but not necessary

The question would then become, to what extent are TDD, pair programming, possibly continuous integration, possibly on-site customer sitting between "nice" "useful" and "necessary".
I'll argue that they are useful and not necessary.

J. B. Rainsberger however attributed the success of the teams who succeeded without XP practices to talented, thoughtful and knowledgeable team members on the team. As per him the Scrum practitioners who are not advocating XP practices are not working in the interest of average development teams who do not have above average talent and cannot succeed without proper engineering practices.

The group did not seem to agree either way on whether Scrum can work without XP or does it need XP to fill in the void on engineering practices. Some people however did mention that they had used a combination of both pretty successfully on their projects.