Shift-left testing

Shifting left moves the tester’s questions to the point where answers are cheap. In refinement that means challenging acceptance criteria. In design it means tracing the journey through the mock-ups, including the error and empty states. During development it means pairing with the developer on a story before it is called done.

It does not mean testers writing more automation earlier, although that can be part of it. The gain comes from preventing the misunderstanding, not from detecting it sooner.

On a banking programme I worked with developers this way, pair testing stories before they were finished, so that problems were settled in conversation before a ticket was needed.