The Number on the Wall
The idea: when a number becomes the goal, it stops telling you what you wanted to know.
Read it
Who is in this book
- Boaz Every metric can be gamed; ask what you are really protecting from CommonsForge
- Opal A measure is a stand-in for something fuzzy; ask what it was standing in for from InquiryForge
- Danya a child of the Green Asks "how do we know?"
- Loop Whatever you reward, you get more of — including the shortcut from SignalForge
- Tara a child of the Green Listens longest, speaks last
Every recurring character has a short tune, so you can tell who is on stage before a word is said. The tunes play only when you tap, and the Reading Access sound switch turns them off.
The Honest Page
Which parts of this story are true, stretched or made up?
True
- In the case, logged minutes went from 90 to 410 a week (more than four times as many) while library loans fell from 312 to 270 a month.
- Goodhart's law is usually put as: when a measure becomes a target, it ceases to be a good measure. It is named after the economist Charles Goodhart. Source
- A related idea, Campbell's law, says that the more a number is used to make social decisions, the more it gets distorted and the more it distorts what it was meant to watch. Source
Stretched
- In the case, the drop in borrowing is caused by the wall. What we simplified: Real numbers rise and fall for many reasons at once. A school would need to compare with other years or other schools before it could be sure the wall did it.
Made up
- The school, the Reading Wall, Mrs. Adeyemi, Dr. Hale and every number in the case are made up.
Tara’s sentence
The case stops where Tara speaks. Write the sentence you would have said. It stays on this device.
Kept.
Your sentence lives on this device. Nothing is sent anywhere.
Ring the hammer for someone
Pick this book for someone younger. The link carries only the book, and it will wait for them on the Green.