Module 01 Summary

What this module established

Working means a rate over a fixed set, judged on properties rather than strings - so the question cannot be answered until the set and the judge exist. Reliability multiplies along the path: five stages at 95-99% each produce roughly one failure in fourteen.

Carry forward

• Rank failures by what they cost the user. Confidently wrong is the expensive one and it is invisible to every operational metric you already collect.
• A testable bar names the set, the dimension, the threshold and the judge. Build the set and measure before choosing the number.
• Name the failures you accept with a mitigation and a residual risk each. A system presented as having none reads as an analysis never done.

Before moving on

Move on when you have an end-to-end target with derived stage targets, and a quality bar naming all four components.

Mark complete