Advanced · Data and analysis · module 137 of 155
Honest charts
Let AI suggest charts and recognise the choices that make a chart misleading.
After this lesson
You choose a suitable chart, check the axis, scale, period and source, and recognise misleading choices in a chart of your own or someone else’s.
In view · Side by side
A fair chart
Line for a trend, bar for a comparison, pie only for parts of one whole.
Does the axis start at zero, and is the period not selectively chosen?
Source, period, unit and processing steps are shown with the chart.
Part 1 of 3 · The right form
Your preference for less movement is on. Choose each part yourself.
Choose the chart to fit the question
A line chart shows a trend over time, a bar chart compares groups, and a pie chart only works for parts of one whole with few categories. AI can suggest a chart or write the code or formula for it (lessons 78 and 109). Include the question and ask why the suggested type fits. Then check whether the numbers in the chart are the same as in your source: a wrong range or a swapped column does not stand out immediately in a nice-looking chart.
Choices that mislead
A vertical axis that does not start at zero can make a small increase look large. A selectively chosen period hides a decline before or after it. Two lines, each with its own scale, suggest a connection that may not exist. A three-dimensional pie makes the front slice bigger than it is. Such choices are sometimes deliberate, sometimes simply a program’s default. Ask with every chart: would someone who only sees the chart conclude the same as someone who knows the figures?
Make the chart verifiable
Put the source, the period and any adjustments, such as rounding or omitted categories, under every chart. Name the unit on the axis. If the axis deliberately does not start at zero, make that clearly visible. Have a colleague look at the chart without explanation and ask what they conclude from it. If that does not match what the figures say, adjust the chart, not the explanation (lesson 129).
New practice example
From explanation to a usable result.
An honest chart fits the question and shows the axis, period and source, so that the reader reaches the same conclusion as someone who knows the figures.
Fictional practice situationFictional: a municipality shows a bar chart of the waiting time at the counter: 18 minutes last year, 15 minutes this year. The vertical axis runs from 14 to 19 minutes.
View a possible solution
This is how it can be done
Because the axis runs from 14 to 19, the waiting time seems almost halved, while it fell by 3 minutes, about 17%. An honest version starts the axis at 0, or adds the drop in figures: “from 18 to 15 minutes”.
Why this works
The reader now sees the real size of the improvement. It is still good news, but without exaggeration.
Make it slightly more difficult
Make a second version of this chart that is misleading, and write down which choice makes the difference. Use them as an exercise, not for publication.
Extra practice, at your own pace. You do not need to submit anything. This does not count towards an automatic assessment.
Your workplace · learning by doing
Make something. See what changes.
Checking the AI connection… You can already view the written example.
Present your assignment to Ende.
Read the answer, change one thing, and compare.
Previously held
New version
You remain in control
What do you want to improve in your next attempt?
On this device only. AI answers remain only in this page memory. This is self-review, not a grade.
Why this approach works
The reader now sees the real size of the improvement. It is still good news, but without exaggeration.
A step further
Make a second version of this chart that is misleading, and write down which choice makes the difference. Use them as an exercise, not for publication.
Try & discover · no obligation
Become the source checker yourself
Only mark statements that the source does not support. Then check your selection.
Fictional chart of the number of members of an association, made with AI for the annual general meeting. A member notes which choices were made.
Select which sentences you would correct above. The answer remains hidden until you check your selection.
This trial works locally with fictitious data and does not count towards your lesson completion. It starts anew with a new lesson or reload.
A prompt to get you started
I want to show these fictional figures: the number of visitors to our museum per month in 2025 (January 1.200, February 1.150, March 1.400, April 1.380). Suggest a suitable chart type and explain why. Give the settings for the axis and the title, and name two choices that would make this chart misleading.
Apply it
A colleague has AI make a chart for the annual meeting. The chart shows only the last three months, in which the number of members rises. Over the whole year, membership fell.
Which approach best fits this situation?
- Keep the chart; it shows what is going well.
- Adjust the axis so the rise looks even clearer.
- Show the whole year, or clearly state the period and that membership fell over the year.
With JavaScript, you can check your approach and receive immediate feedback.
Test your insight
A chart shows an increase from 98% to 100% satisfaction, with an axis that starts at 97%. What is the problem?
- There is no problem; the chart shows the correct figures.
- The truncated axis makes a small increase of two percentage points look large.
- The chart should be a pie chart.
Extra practice
Find a chart in a report, a news item or one of your own presentations. Check the axis, scale, period and source, and write down what someone would conclude from it without the figures.
Chart: a line chart of visitors per month. Axis: from 0 to 1.500, unit visitors. Title: “Visitors per month, January to April 2025”. Under the chart: till system, export of 2 May 2025. Misleading would be: starting the axis at 1.100, which makes the increase in March look huge, or showing only February and March.
