There is nothing in the Scrum Guide that says roles cannot be combined. This is true for core roles such as Product Owner and developer, and also for complimentary roles. A Scrum Master would not be breaking any rules if they also served as a technical architect; project manager; coffee shop assistant; finance director; or line manager for members of the team.
It is for each team and organisation to decide what makes sense for them, and what risks, conflicts of interest, or time management issues might arise. For example, a scrum master may encounter:
- Time management issues if they had to work in the coffee shop for an 8 hour shift every day
- A conflict of interest between optimising the system for value vs delivering on time, on budget if they were also a project manager
- Risks of not being able resist pressuring the team to over-commit during time-critical delivery scenarios if they also served as a product owner
Line management is an essential role for all organisations. If done well, it can result in significant benefits to staff and their organisation:
- Career development
- Increased skills and productivity
- People feeling valued and motivated
- Having an accountable person to take the lead in managing problems if they arise
In practice, there have been cases where scrum masters have fulfilled this function, and it’s possible to be successful with the right approach. If considering this arrangement, the following conflicts with the scrum master role should be anticipated and mitigated:
Coaching – Scrum Masters provide this service on the basis that teams and individuals take ownership of the decisions and outcomes. This works better when the coach isn’t directly accountable for the actions and decisions of the people they are coaching.
Leadership – Scrum Masters lead by example and provide an enabling function without detracting from the teams autonomy. This works better without direct authority, regardless of whether you choose to use it, because teams retain ownership of outcomes.
Organisational HR policy – Part of the role of the Scrum Master is to coach the organisation to make the most of Scrum. Sometimes this might include advising the organisation on the effects of established HR policy, such as the way promotions and pay rises are handled. If HR policy is effective, there would be little impact; however, if HR policy was creating problems with team motivation or alignment, then a good scrum master should seek to highlight these problems and influence change. This is more challenging if the scrum master is accountable for implementing existing policy. It can also affect the dynamic between the Scrum Master and members of the team if they play a role in evaluating their performance.
In summary, line management is an essential function that can have a positive or negative effect on team capability. Like other functions, it takes skill and experience to do well, and there are risks of conflict of interest. In deciding who should perform the role, consideration should be given to the people available, their skills and experience, and how it might impact their existing responsibilities. There are usually better options than the Scrum Master, but if not, an awareness of the potential issues above will increase the chances of that person leading effectively.