Your question is Measure Process Improvement Impact. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You've changed an engineering process and want to know whether it actually improved outcomes. You need a way to separate real improvement from normal week to week noise, and to look beyond a single headline metric.
How do you measure whether a process improvement actually worked?