DM: Interpreting Complex Information

Data Interpretation in Decision Making

Some DM questions present tables, charts, graphs, or text-based data and ask you to draw conclusions. Unlike QR (which focuses on calculations), DM data interpretation focuses on logical conclusions — what the data supports, what it does not support, and what additional information would be needed.

Reading Data Critically

When presented with data, systematically check:

1. Title and labels: What exactly is being measured? What are the units?
2. Time period: Over what period was data collected?
3. Scale: Is the axis truncated or manipulated? Does the scale start at zero?
4. Sample: Where did the data come from? How large is the sample?
5. Missing data: What is NOT shown that might change the interpretation?

Common Traps in Data Interpretation

• Truncated axes: A bar chart starting at 90 instead of 0 exaggerates small differences
• Percentages vs absolute numbers: “50% increase” sounds large but could be from 2 to 3
• Cherry-picked data: Showing only data points that support a conclusion while omitting others
• Confusing correlation with causation: Two variables moving together does not mean one causes the other
• Ignoring confounding variables: A third factor could explain both observed trends

Multi-Source Data Questions

Some questions provide data from multiple sources (e.g., two tables or a table and a text description) and require you to synthesise information across sources. Strategy:

1. Understand each source independently first
2. Identify what connects the sources (common variables, shared categories)
3. Draw your conclusion from the combined information
4. Check that your conclusion is supported by BOTH sources, not just one