The three parts of a data story

By the end of this lesson you can name the question, the evidence and the answer in any short report.

Why it matters

Your numbers only help if someone understands them. A short, clear data story is how analysis turns into a decision. It is often the only part of your work a busy person reads.

The idea in plain words

Think of a good news report about a football match. It tells you which match (the question), the key facts (the evidence: goals, who scored, when), and the result (the answer). You could check every part.

A data story has the same three parts:

1. Question: the clear question you set out to answer (lesson 3.1).
2. Evidence: the numbers, how you got them, and usually one honest chart.
3. Answer: what the evidence means, in plain words, and what it cannot tell you.

Data story: a short piece of writing that gives a question, the evidence from data, and the answer, so a reader can understand and check it.

Evidence: the facts that support an answer. In a data story: the numbers, where they came from, and how they were worked out.

Question, evidence, answer. Every good data story has all three.

See it done

Amara is deciding whether to get a card machine. She asks: "How do my customers pay?"

Data: market-stall-week.csv (synthetic).

1. Write the question clearly. "How did customers pay at Amara's stall from 2 to 7 March 2026?"
2. Gather the evidence. With COUNTIF (lesson 3.5): Cash 28, Transfer 20, Card 12.
3. Check it. 28 + 20 + 12 = 60, the number of sales. Nothing missed or counted twice.
4. Make one honest chart. A column chart of the three counts, with the axis from 0 (lesson 4.4).

The evidence as a picture: cash is the tallest bar.

5. Work out a simple share. 28 out of 60 is just under half. Per hundred sales, that is about 47: 28 ÷ 60 × 100 = 46.7, which rounds to 47.

Percent: "out of every 100". 47 percent means 47 out of every 100. To work it out: part ÷ whole × 100.

6. Write the answer, with its limits. "Cash was the most common way to pay: just under half of all sales (about 47 in every 100). This covers one week at one stall, so it may not hold for other weeks."

About 75 words. Anyone can read it in under a minute, and check every number.

Your turn, with help

Write a three-part data story for Lucía: "How do the pupils in both classes get to school?"

Hint: you made this summary table in lesson 4.4 (Walk, Bus, Bicycle, Car). Check the four counts add up to 30.

Show a model answer

• Question: How do the 30 pupils in Lucía's classes 5A and 5B get to school, according to the March 2026 survey?
• Evidence: Bus 14, Car 8, Walk 4, Bicycle 4 (counted with COUNTIF; 14 + 8 + 4 + 4 = 30).
• Answer: The bus is the most common way: 14 of 30 pupils, just under half. This is one survey of two classes at one school.

Your turn, alone

1. Write a three-part data story answering: "On which day did Amara make the most sales from 2 to 7 March 2026?"
2. Which part of a data story is missing here? "Cash was the most common way to pay at Amara's stall, 28 of 60 sales. This covers one stall only."
3. Work out what percent of Amara's 60 sales were paid by card. (Card: 12.)
4. Why should the answer part say what the data cannot tell you?

Check your answers

1. For example: Question: On which day did Amara make the most sales from 2 to 7 March 2026? Evidence: Mon 10, Tue 9, Wed 8, Thu 11, Fri 12, Sat 10, counted with COUNTIF; they add up to 60. Answer: Friday, with 12 sales; Wednesday was quietest with 8. One week only.
2. The question. It gives evidence, an answer and a limit, but not the question with its "when".
3. 12 ÷ 60 × 100 = 20 percent.
4. So the reader does not stretch the answer further than the data goes (for example, to other weeks or other stalls).

Watch out

• Starting with the numbers. Lead with the question, so the reader knows why the numbers matter.
• Evidence nobody can check. Say where the numbers came from and how (the dataset, the formula).
• Long stories. If it is more than a short paragraph, cut. Every sentence should earn its place.

Say it back

1. Name the three parts of a data story.
2. What does "percent" mean?
3. What did the payments story say about its limits?

Show the answers

1. Question, evidence, answer.
2. Out of every 100.
3. It covers one week at one stall, so it may not hold for other weeks.

What is next

A data story is only as good as its numbers. Before you share one, you check it. Next lesson: a five-step check that catches a real mistake hiding in a draft.