[Saheil Sarkar] Scrum is rooted in empiricism, and it has been empirically observed that conducting a Daily Scrum with team sizes ranging from 5 to 9 members should typically be completed within a 15-minute timeframe. This concept I also learnt in the book "Scrum: The Art of Doing Twice the Work in Half the Time."

[Rituraj Patil] The Scrum Guide authors were inspired by the Three Bears. They wanted to find timebox values that were not too long, not too short, but just right.

For the Daily Scrum, they tried 14 minutes and found it was too short. They tried 16 minutes and found it was too long. Finally, they tried 15 minutes and found it was just right.

The same process was followed for the other Scrum events.

Of course, these are just jokes.

The real answer is that the Scrum Guide authors carefully considered the needs of Scrum teams when choosing the timebox values.

Timeboxes are important because they help to keep Scrum teams focused and efficient. They also help to prevent meetings from dragging on too long.

The Scrum Guide authors wanted to choose timebox values that would be realistic for most Scrum teams, but also flexible enough to be adjusted as needed.

And so, the 15-minute Daily Scrum was born.

[Patralekh Satyam] I believe, it is important to note that while 15 minutes is the standard recommendation for the Daily Scrum, Scrum is a flexible framework that allows for adaptation. Scrum Masters and Scrum teams should adopt a pragmatic approach and keep the essence of the Daily Scrum in mind, which is striking a balance between brevity and ensuring everyone has an opportunity to communicate.

If a team consistently finds that a 14 or 16-minute duration works better for them, they can make that adjustment. However, it's crucial to exercise caution and conduct due diligence before implementing such a change. The team should have a solid justification for deviating from the standard duration.

Teams should also be vigilant about preventing non-Daily Scrum discussions from infiltrating the meeting. Allowing a change from 15 to a 16-minute meeting gives easy access to further stretch it to 30 minutes and then to a 45-minute status update meeting, which must be avoided to maintain the meeting's intended purpose and efficiency.

[Pooja Mhamunkar] The timebox values in the Scrum Guide, like 15 minutes for a Daily Scrum, are set to strike a balance.
They are designed to ensure that meetings are long enough for effective communication and decision-making but short enough to avoid wasting time.
For example, 15 minutes for a Daily Scrum encourages a quick update among team members, allowing them to discuss their work and plan for the day without delving into unnecessary details.
If it were longer, it might lead to more in-depth discussions that could be handled separately.
If it were shorter, important updates might get rushed or missed. So, these timebox values aim to optimize productivity and collaboration within a Scrum team.