The most dangerous data is data that looks precise, but is wrong.

What “Good” Data Looks Like in Practice

• Clear definition: Everyone knows what is being measured.

• Consistent collection: It is gathered the same way each time.

• Fit for purpose: It matches the decision you are making.

• Comparable: It allows trend checks over time.

Five Common Traps School Leaders Fall Into

1. Vanity metrics: Easy to track, hard to use.

2. Snapshot thinking: One result becomes the whole story.

3. Over-interpretation: Tiny changes get big reactions.

4. Confirmation bias: We notice what fits our view.

5. False precision: Numbers look objective, but the method is weak.

A Practical Rule

If the measure is high-stakes, confirm it with a second source.

Reflection Prompt

Where have you seen leaders react too quickly to one data point?