The other day I had an intense conversation with managers about the topic of double roles of a Scrum Master. One of the managers was also a Scrum Master. He and his superior defended the viewpoint that it is a great idea to have one person being the line manager for the teams and at the same time being the Scrum Master for the same team. Based on my observations about the typical dysfunctions created by this kind of set-up, I express my thinking that the Scrum Master must be a dedicated role if the organization is seriously wanting to introduce Scrum. As a result, I was labeled kind of religious and “inflexible to adapt to their thinking”.
My first learning was that it is pointless to convince others of your view and the statement “own versus rent” has proven itself once more. People need to generate those insights by themselves and not be told by a “guru”.
I dug up some of my old work on this subject and I present you with an overview of different combinations I have seen during my work life including my view on the pros and cons.
Conclusion
I can not recommend any of these combinations as the cons in all those combinations outweigh the pros. Most companies do the combination for saving money, and this is in IMHO the wrong place to start saving money. Having a dedicated Scrum Master allows this person to fulfill the role of an SM without conflicts of interest, and support, coach, help the teams, the PO, and especially work with the organization (in collaboration with the managers) to create the environment in which teams can succeed.
What to do about it?
The biggest hurdle seems that organizations need to do their own learning. Therefore I suggest you make experiments in your organization. Try out a dedicated Scrum Master in comparison to the combination you face in your organization. Reflect after 2-6 Sprints on the results, and then adapt based on your findings. Yes, this will take time and energy. The easier way might be to follow the principle of Shu-Ha-Ri and adopt the collective learnings from the past 15 years (and e.g. the empirically-created LeSS rule): The Scrum Master is a dedicated role.