Grade 8 · Unit 7: Telling the story¶

Track: A (no-code) · Tools: poster paper, markers, optional spreadsheet · Lessons: 3 Datasets: class-survey-synthetic, census-districts

Big idea. Data only matter when someone understands them. A good data story makes one clear claim, backs it with evidence, and is honest about what it cannot say.

What you will be able to do

I can write a claim, evidence and reasoning (CER) statement.
I can design a clear one-page data poster.
I can give and use specific, kind feedback.

Words to know: claim (दाबी), evidence (प्रमाण), reasoning (तर्क), audience, headline, caption, limitation. Full list: curriculum/framework/glossary.md.

Before you start¶

You now have everything for the last step of PPDAC, the Conclusion: a question (Unit 2), data (Unit 3), graphs (Unit 4), summaries (Unit 5) and fair comparisons (Unit 6). This unit is about turning them into a message.

Lesson 1: Claim, evidence, reasoning¶

Hook (5 min). A classmate says: "Our class sleeps too little." Is that a claim? What would prove it? What would disprove it? What would you need to know first?

Explanation¶

Scientists, lawyers and journalists all use the same three-part structure to argue from data, called CER:

Here is an example from Section B of a school in Butwal, who ran their own sleep survey:

Claim — a clear, specific answer to the question. "Most students in our class sleep less than 8 hours on school nights."
Evidence — the data that support the claim: numbers with units, a graph, the source. "20 of 36 students (56%) reported less than 8 hours; the median was 7.8 hours (class survey, 36 students, May 2026)."
Reasoning — why the evidence supports the claim, and how far. "Doctors recommend 8–10 hours for 13–18 year olds, so more than half the class is below the recommended amount. This is one class and one week, and sleep was self-reported, so we cannot say this is true for all Grade 8 students."

Good reasoning includes a limitation: who the data cover, how they were collected, and what else might explain the result. Admitting limits makes a story more trustworthy, not less.

The claim must match the evidence. Watch for these leaps:

Evidence	Over-claim	Matching claim
10 classmates walk	"Nepali students walk to school"	"In our sample of 10 classmates, all walk"
Students who sleep more have higher marks in our class	"Sleep causes good marks"	"In our class, students who sleep more tend to have higher marks"
Literacy rose from 60% to 66%	"Literacy has been solved"	"Literacy improved by 6 percentage points"

Words like "tend to", "in our sample", "about" and "we found" are honest. Words like "all", "always", "proves" and "causes" need very strong evidence.

Activity (20 min)¶

Your teacher gives three claims about the class survey (or use: "Students who walk take longer to reach school." "Maths is the most popular subject." "Students with more siblings sleep less.").
For each claim, look at the class table and write the evidence (numbers and units).
Write the reasoning, including one limitation.
Rate each claim: ✅ supported, ⚠️ partly supported, ❌ not supported. Rewrite any over-claim so it matches the evidence.

Common mistakes¶

A claim with no number ("Many students walk").
Evidence that does not match the claim (a graph of travel mode to support a claim about travel time).
No limitation, or a limitation so general it says nothing ("data can be wrong").

Check (5 min). 1. What is evidence? 2. What does reasoning add? 3. 10 classmates walk. Claim: 'Nepali students walk to school.' OK?

Reflect (2 min). What surprised me? Who or what is missing from this data?

Lesson 2: Poster design¶

Hook (5 min). Walk past two posters on the wall. One you understand in 10 seconds; one you cannot understand at all. What is different about them?

Explanation¶

A data poster is read by people walking past. They give it 10 seconds. If the message is not clear in 10 seconds, most will walk on. So design for the 10-second reader first and the 2-minute reader second.

Layout of a one-page data poster

┌──────────────────────────────────────────────┐
│ HEADLINE = your claim, in one sentence       │
│ (big letters, readable from 2 metres)        │
├──────────────────────┬───────────────────────┤
│                      │ Key numbers           │
│   MAIN GRAPH         │  • 56% sleep < 8 h    │
│   (the evidence)     │  • median 7.8 h       │
│   title, axes, units │                       │
├──────────────────────┼───────────────────────┤
│ Second graph         │ Our question & method │
│ (optional)           │ (who, how, when)      │
├──────────────────────┴───────────────────────┤
│ What we CANNOT say from this data            │
│ Source · date · who made it                  │
└──────────────────────────────────────────────┘

Design rules * Headline = the claim, not the topic. "Most of us sleep less than 8 hours" beats "Sleep survey". * One or two graphs, not six. Each graph earns its place by supporting the claim. * Captions under each graph: one sentence saying what to notice. * Highlight the important part (one bar in a strong colour, others grey). * Big text, few words, plenty of empty space. If you need a paragraph, it belongs in the report, not the poster. * Source and date always; and a box for what we cannot say (the limitations). * Accessible colours: about 1 in 12 boys cannot tell red from green; use dark/light or blue/orange.

Activity (20 min)¶

Sketch (in pencil, on A4) a poster layout for the claim you liked best in Lesson 1.
Swap with another group. Give two stars and a wish: two things that work, one specific thing to try.
Test the 10-second rule: show your sketch to someone for 10 seconds, take it away, and ask what the message was.

Common mistakes¶

A headline that is a topic, not a claim.
Too many graphs, too much text, tiny letters.
Missing source, date or units.

Check (5 min). 1. What goes in the headline? 2. Name two things every graph needs. 3. Why add a 'what we cannot say' box?

Reflect (2 min). What surprised me? Who or what is missing from this data?

Lesson 3: Feedback and presenting¶

Hook (5 min). How do you feel when someone looks at your work and says only "wrong!"? What would be a more helpful thing to say?

Explanation¶

Feedback helps work improve, if it is: * Specific: "The y-axis has no unit" rather than "the graph is bad". * Kind: about the work, not the person. * Useful: something the person can actually change.

The two stars and a wish format forces all three: two specific strengths, one specific suggestion. Example: ⭐ "Your headline tells me the claim immediately." ⭐ "Highlighting the 'walk' bar in blue made it easy to see." 🌱 "Wish: add the number of students surveyed, so I know how big the sample was."

Receiving feedback is a skill too: listen, write it down, ask a question if unclear, then decide what to change. You do not have to accept every suggestion, but you should be able to say why.

The one-minute data talk has three parts: 1. Claim (10 seconds): "We found that most students in our class sleep less than 8 hours." 2. Evidence (30 seconds): point at the graph. "This bar shows 20 of 36 students… the median is 7.8 hours." 3. Limit and next step (20 seconds): "This was one week and self-reported. Next we would like to compare with Grade 10."

Speak to the audience, not to the poster. Point at the graph while you talk about it.

Activity (20 min)¶

In pairs, rehearse your one-minute talk using a timer.
Your partner gives two stars and a wish using the talk checklist: claim clear? evidence with numbers and units? limitation stated? under one minute?
Swap roles. Then each person writes down one change they will make.

Common mistakes¶

Feedback like "nice" or "bad" that gives nothing to act on.
Reading the poster aloud instead of explaining it.
Running out of time before the limitation.

Check (5 min). 1. What is a 'wish' in feedback? 2. What three things go in a 1-minute talk? 3. Why avoid saying only 'good' or 'bad'?

Reflect (2 min). What surprised me? Who or what is missing from this data?

Unit summary¶

A data story = claim + evidence + reasoning (with a limitation).
The claim must match the evidence: "in our sample", "tend to", "about".
A poster's headline is the claim; one or two graphs; captions; source, date; "what we cannot say".
Design for the 10-second reader.
Feedback is specific, kind and useful: two stars and a wish.
A one-minute talk: claim → evidence → limit and next step.

Practice exercises¶

★ Label each sentence C (claim), E (evidence) or R (reasoning): (a) "The median travel time was 29.5 minutes." (b) "Most students live within half an hour of school." (c) "Because the median is below 30 minutes, at least half the class reaches school in under half an hour."
★ Turn these topics into claim headlines (invent sensible numbers if needed): "Travel to school", "Favourite subjects", "Mobile phone use".
★★ Write a full CER statement using the class table for: "Walking is the most common way to reach school."
★★ Rewrite each over-claim: (a) "Everyone in Nepal loves momo" (from a survey of 20 friends); (b) "Using phones makes students fail" (from one class's data); (c) "Our school has the best results in the country" (from comparing with two nearby schools).
★★ Give two stars and a wish for this poster description: Title "Data". Three pie charts with 8 colours each. No source. A paragraph of 200 words. One sentence at the end: "So students should sleep more."
★★ Write a one-minute talk script (about 120 words) for the claim in exercise 3.
★★★ Which is the stronger limitation, and why? (a) "Our data might have mistakes." (b) "We asked students about sleep on a Monday after a holiday weekend, so they may report more sleep than on a normal school night."
★★★ A poster about the synthetic district table says: "Hill districts are smarter." Explain two things wrong with this claim and write a better one.
★★★ Section B's claim was "Most students sleep less than 8 hours." Test the same claim on the synthetic class table (sleep_hours, 36 students). Count the students under 8 hours and find the median. Is the claim supported for this class? Write the CER statement you can make.

Exercises with real data¶

R1. A real data story (RD-02). Choose one Our World in Data chart about Nepal (child mortality, life expectancy, CO₂ per person, internet use). Write a CER statement and sketch a poster with the chart as main graph, including the source line and a "what we cannot say" box.

R2. Fact-check a headline (RD-01 / RD-13). Find a recent news article about Nepal that uses a number (population, remittances, inflation, tourist arrivals). Find the original source of the number (NSO, Nepal Rastra Bank, World Bank). Does the headline match the evidence? Write two stars and a wish for the journalist.

R3. Class + district poster (flagship). Combine your class survey with one district-level table (synthetic or the real census for your district) for the unit project below.

Unit project: Our class, our school poster¶

Follow Problem · Plan · Data · Analysis · Conclusion. Make a one-page poster from your class survey plus one district table: a claim headline, one or two graphs with captions, key numbers, method box, "what we cannot say" box and source. Present it in a one-minute talk and respond to feedback. This is Grade 8's flagship project. Full brief and rubric: project.md.

If you use an AI assistant, follow the AI-use policy (explain, don't answer; disclose; be ready for an oral check).

Going further¶

Our World in Data's articles show how to write about data honestly: read one short article about Nepal or South Asia and find its claim, evidence and limitations.
Cole Nussbaumer Knaflic, Storytelling with Data (2015): the classic book on clear charts and slides (Grade 12 Unit 7 uses its ideas).