In Project Management, for any given series of tasks you are only concerned with how much work you have left to do and how much time you have left to do it.
From there we can create score based on the value of work done vs the amount budgeted for that work to be done.
To make it simple, let's say each bug they committed to fixing was worth $10 which breaks down to $35 per week.
4 bugs were fixed, so $40 worth of work was done compared to the budgeted $35
The SPI (Schedule Performance Index) = Earned Value ($40) / Planned Value ($35
SPI = 1.14
So, in a weekly update to senior management, they'd see the SPI is above 1 and know it's ahead of schedule and under budget. There would be a couple more Reporting Indexes they'd glance at, but you get the point.
