Build an audit that identifies the problem, uses evidence and explains a better representation.
Lesson 07 · StatisticsYour learning goal
Critique and improve a graph, identify unsupported conclusions and justify corrections using data and context.
Use a claim–evidence–reasoning structure
Begin with a specific judgement about the representation. Quote or describe the relevant feature, cite the data and explain the effect. ‘The graph is bad’ is a reaction. ‘The cropped bar axis makes a change from 96 to 100 look much larger than its approximately 4.17% increase’ connects a design choice to a mathematical consequence.
Separate the graph from the headline
Check whether the plotted values match the data, whether the representation suits the question, and whether the headline follows from the evidence. These are related but separate checks. A correctly plotted graph may accompany an unjustified causal claim. An attractive graph may omit a group or time period needed to test its conclusion.
Improve without rewriting the evidence
Choose changes that address the identified problem: a clearer graph type, a shared scale, accurate labels, consistent units or missing context. Keep the recorded values intact. If the source itself is ambiguous or inconsistent, flag the issue and request clarification; do not silently invent a corrected dataset. Keep your reconstruction separate from the original evidence.
Explain why your version is better
A correction should make the intended comparison easier and fairer. State what changed, what stayed the same and what conclusion is now supported. A good audit also describes limitations. If the sample is small or unrepresentative, a better graph cannot remove that limitation from the underlying evidence.
Explore · predict, test, explain
Make your thinking visible.
The correction desk
Repair this display: replace its overstated title, restore a zero baseline and explain what the values support.
Line graphs use equally spaced positions here: use observations at equal time intervals. Do not use a line to connect unrelated categories. Circle graphs require a positive total.
Compare a worked audit after trying
A neutral title such as “Recorded sales before and after” and a zero-based bar graph show the increase without exaggerating visible lengths. Sales rose by 4 units, approximately 4.17%. The two observations do not establish the cause.
Worked examples
Follow the reasoning.
A complete short audit
Claim: the display exaggerates a small increase in sales.
Evidence: the values are 96 and 100, while the bar axis begins at 90.
Reasoning: visible lengths of 6 and 10 suggest a much larger proportional difference than the actual values.
Correction: show bars from zero, retain the values and units, and report the approximately 4.17% increase without claiming a cause.
When the evidence is incomplete
A circle graph reports 35%, 30% and 20%, with no explanation of the remaining 15%.
The shown values total 85%. Ask whether a category is missing or the reported percentages use a different denominator.
Do not scale the three percentages to 100% and pretend they are the original complete data.
Record the uncertainty and request the original counts or an explanation of the omitted category.
Guided Practice
Build an explanation.
A graph is accurate but says a new logo caused higher sales. What should your audit distinguish?
Give me a hint
Check the numerical representation separately from the proposed cause.
Compare a worked response
The graph may faithfully show a rise while the causal claim remains unsupported. Explain what additional comparison or investigation would be needed to evaluate the logo’s effect.
An evidence story and graph do not match. Should you rewrite the story to make them agree?
Give me a hint
The task is to audit the evidence, not erase the inconsistency.
Compare a worked response
No. Preserve both originals, describe the mismatch precisely, cite the relevant values or labels and explain what clarification is needed. Build a separate corrected representation only when the source data is established.
Independent Practice
Test the idea, then check your reasoning.
Feedback explains your chosen response. These activities are practice, not a school mark.
Connections
Use it beyond this page.
Apply this audit structure to Case Files: Misrepresentation. Work from the original evidence, draft your correction separately and use data to justify every proposed change.
Take it further
Give a partner your corrected graph without your explanation. Ask them to infer the intended conclusion. Revise your labels or reasoning if the graph still invites an unsupported interpretation.