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Data and Society 9-12 / Week 06 / Mission Quest
6/6
Week 06 · Cleaning Data

Mission Quest

Mission Quest: The rule box
// Fixing messy data without changing what it means
⏱ about 20 min

Mission Quest: The Rule Box

Keeper Ines sets a cardboard box on the workbench. It holds the Commons lost-and-found: gloves, pencils, a scarf, two books and a single sock.

"Can you sort this?" she asks.

Comet starts at once. "Clothes here, school things there." Then she picks up a pencil case. "Hmm. Is this a school thing or a bag?"

Wren tries the same box and makes different piles. "What do you notice?" he asks. "Our piles do not match."

Nova hovers over the two sets of piles. "Would you like a hint?" she asks. "Write the rules first. Then anyone who follows them should make the same piles."

Comet grabs a pencil. "Rules first, again!"

  1. Messy data are not uniform. Cleaning makes them uniform without changing meaning.
  2. Write cleaning rules before you change anything.
  3. Mark blank or invalid answers. Never fill in a guess.
  4. Keep a log of every choice you had to think about.
◇ THE RULE BOX
You need a family member, paper, a pencil and 15 to 20 safe, everyday items in a box or basket.
Good items: socks, pencils, spoons, books, toy blocks, cups, hair ties and keys.
Together, write three to five sorting categories and one rule for each, such as "Things you wear go in clothes."
Add an "other" pile and a rule for when an item fits two categories.
You sort the box first, using only the written rules. Keep a log of any item you had to think about.
Mix the items again. Your family member sorts them, using only the same rules.
Compare the two sets of piles. If an item landed in different piles, fix the rule together.
Sort one more time and see if the piles now match.
For a grown-up
This week your student learned to clean data: make answers uniform without changing what people meant.
Ask: why is it not fair to fill in a blank answer with a guess?
Ask: how did writing the rules down change how well your piles matched?
Everything in this course is done on paper. No app, website or account is needed.
QUEST CHECK
  • Read the question.
  • Tap your answer.
You and your family member made different piles. What is the best next step?
An item fits two categories. What do you do?
Quest reviewTrue or false?
Good sorting rules let two people make the same piles.?
You should write the rules after you finish sorting.?
A log helps others see why you placed a tricky item.?
WHY THIS EXERCISEWritten rules and a log are what make cleaning fair and repeatable.
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