A team member is taking too much time at Daily Scrums. What is the best way to resolve this issue as a Scrum Master?
Can I intervene at the Scrum?
According to the Scrum Guide:
The Scrum Master teaches the Development Team to keep the Daily Scrum within the 15-minute time-box.
One of the responsibilities of the Scrum Master is also:
Facilitating Scrum events as requested or needed
So - yes. It is the responsibility of the Scrum Master to teach the Development Team techniques for an effective Daily Scrum and to keep it (and other events) to the timebox. You would do this by coaching both the team and the individual in the purpose of the Daily Scrum.
However, before getting involved, I'd ask a few questions:
A Sprint Retrospective is a good opportunity to have this discussion with the team. Although if you are running longer Sprints or it's a very common issue that's impacting the team's performance, it's OK to have the conversation sooner.
The Daily Scrum is supposed to be useful for the team. That's not a reporting meeting, that's a place where activities are shared to foster contribution.
A team member is taking too much time at Daily Scrums.
How much is too much? Has your team complained about it? Has the meeting broken the advised 15 min threshold?
Scrum is a tool, and adhering to it for the sake of adhering to it could be dangerous. Improve your delivery quality should be the target, not to stick to ceremonies. Scrum suggests co-located teams between 7+-2 people. Is your team aligned to it?
Assuming the team has complained about it: then may be a matter of having a private conversation with this specific developer, appreciating all the details being provided and at the same time explain to him that the team may not need this specific level of detail during daily scrums.
Assuming the details provided are valid (i.e. team appreciates them) but 15 minutes rules are being broken: then may be a matter of having a team conversation to understand if the Daily Scrums could be short or more objective (i.e. focusing only on today's activities, leaving more details to subsequent chats, etc.). If your team considers that during specific periods a few minutes more are needed, then try it. Don't be afraid to experiment. The team eventually will improve and naturally will reduce the time taken.
Scrum is a tool, not the goal. Focus on the delivery. If you can deliver more value doing 20 minutes Daily Scrum, go for it.
Yes, it is your responsibility as the scrum master. In every agile team I've been on, the scrum master has worked to help us keep our responses under the 15 minute time limit overall.
That being said, you don't necessarily need to address the time length directly, but if you do, make sure it comes across with a positive tone and it's likely to be better received. In other words, rather than saying "we're taking too long at standup" say something like "I'd like to try a new format / a different approach to standups and see how everyone likes it." Notice that you need not directly address an individual; instead, challenge the team to keep the working agreement all together.
Agile is intended to be tweaked and adjusted as you go, and the team as a whole should decide and agree on what those changes are. If the team as a whole agrees they want to spend less time on the scrum meeting, then it won't be you getting involved so much as just the Agile way of working, well, working.
Here are some ways you can indirectly address it that have worked well in my experience:
If worst comes to worst, have a timer that keeps people's responses under a certain time, beeping loudly when the time is up (I've never seen this need to be used). The amount of time would need configured for your individual team, and the idea would be to eventually not need it anymore once people have learned to make their updates more concise.
I would only intervene at the scrum if the team has agreed the responses should be shorter, and one person in particular continues to ignore this working agreement and go well beyond the allotted time. In this case, it would be appropriate to bring up the working agreement and ask them to work on shortening their responses. It would probably be better to discuss with them first in person, rather than in front of the whole team.
If it continues to happen, it may be necessary to stop them mid-ramble and say something like "can we have the short version now and discuss the fine print later?" Some people may not realize how much time they've taken unless it's pointed out to them as it's happening.