Many new leaders of scrum teams want to know what the burndown chart "should" look like. Some even start running statistical calculations on the data (I once worked with a 'coach' that had a spreadsheet custom designed to extract just such anomalies). The best answer I've given is a session on the whiteboard to explain:
- how the data is obtained
- how accurate & precise the data is - just good enough & not any better
- interruptions that MAY be made ... but only by the TEAM
Let's go one at a time.
They are learning to make their work visible... praise this effort - it can be quite scary to show your work.
Do not use tools that show this mathematically perfect line from start to finish. Only robots are capable of such precession, and only with the perfect PLAN.
If you see something like this in the first 3 or 4 sprints... it is a good sign. Now reduce the scope of work by at least HALF.
This is what a great team of high performing collaborating team mates can achieve.
What if the performing team does this 3 sprints in a row?
A performing team that can PULL in work can increase their Velocity - this is the only way to see acceleration. PUSHING will not work.
[speller errors are to be blamed upon the ink pen]