Thinking Habit 2: Question Assumptions
Thinking Habit 02
Question
Assumptions
Identify what you are taking for granted and examine whether it is justified.
Driving question
What am I assuming, and what supports that assumption?
Teacher prompts
- What are you treating as true without checking?
- What would need to be true for your conclusion to follow?
- What evidence supports that assumption?
- If the assumption were wrong, what would change?
What students do
- Identify an unstated idea behind a claim, interpretation, or plan.
- Separate what is given from what they have assumed.
- Check whether the assumption has support in this context.
- Revise or qualify their conclusion when an assumption is uncertain or unsupported.
See the habit in the work
A student uses a survey to recommend a school club. Questioning who the survey represents changes how far the student can take the results.
Illustrative classroom example · Interpreting survey results
Draft conclusion
Most students at our school want a chess club.
The information available
In a lunchtime survey, 16 of 20 students sitting at the board-game table said they would like a chess club.
The conclusion assumes that students at this table represent the preferences of students across the school.
Draft conclusion
Most students at our school want a chess club.
Teacher feedback
Who answered the survey? What are you assuming when you use their answers to describe the whole school?
Ask the student to check how participants were selected and whether students with different interests had a chance to respond.
Draft
Most students at our school want a chess club.
Revised
Most students surveyed at the board-game table want a chess club. We do not yet know whether most students across the school do.
What changed: The student identified the assumption that one group represented the school, checked how the sample was selected, and limited the conclusion to the group surveyed.
Try it in class
Surface an assumption
- Choose a claim, interpretation, or plan from the current lesson. Ask students to list what is directly given.
- Have them complete: “For this to hold, we are assuming that…” Choose one assumption that matters to the conclusion.
- Ask what supports the assumption and what could challenge it. Have students retain, qualify, or revise the conclusion and explain why.
Make the assumption visible
Have students record the original claim, an assumption it depends on, what they checked, and the resulting conclusion.
Look for a specific assumption and a reasoned check of it. Questioning an assumption does not require rejecting it: students may retain it when the available evidence supports its use.