Common Cause Variation
Why Blaming Workers Doesn't Work: Common Cause vs. Special Cause Variation
The red bead experiment reveals one of the most important — and most ignored — lessons in management.
Imagine you’re a manager overseeing a production line. On Monday, one worker produces 4 red beads — far above average. You pull them aside for coaching. On Tuesday, a different worker produces only 1 red bead. You praise them in front of the whole team.
By Friday, nothing has changed. The red beads keep coming. And you’re running out of explanations.