Concept
1. Start with the message, not the chart
Write the one sentence the chart must prove before you insert anything:
- "Sales dropped every month this quarter." → trend
- "North sells almost twice as much as South." → comparison
- "Electronics is 72% of revenue." → composition
- "Most orders are under ₹50,000." → distribution
- "Stores with more orders don't have bigger order values." → relationship
That sentence also becomes the chart title.
2. The matrix
| Question type | Best charts | Avoid |
|---|---|---|
| Trend (change over time) | Line; column for few periods; sparklines | pie, bar (horizontal) |
| Comparison (between items) | Bar (horizontal) for many/long names; column for few | 3-D anything, pie with many slices |
| Composition (parts of a whole) | Stacked bar/column, 100% stacked, waterfall; pie/donut only for 2–4 parts | many-slice pies |
| Distribution (spread of values) | Histogram, box & whisker | average-only bar |
| Relationship (two measures) | Scatter, bubble | two separate charts |
3. Examples with our data
| Message | Chart |
|---|---|
| Monthly revenue Apr 2025–Mar 2026 with a Diwali peak | Line chart (12 points) |
| Revenue by store, 8 stores | Horizontal bar, sorted largest first |
| Category share of FY revenue (Electronics 72.4%, Furniture 14.0%, Kitchen 12.1%, Home Decor 1.5%) | 100% stacked bar or sorted bar with % labels |
| Order value spread | Histogram |
| Revenue growth FY24-25 → FY25-26 by region | Waterfall |
4. Five quick rules
- One message per chart. Two messages → two charts.
- Sort categories by value (unless they have a natural order like months).
- Label directly instead of making people read a legend (Lesson 6).
- Start bar/column axes at zero (Lesson 6).
- Title = the conclusion, e.g. "West grew slowest: +6.3% YoY", not "Revenue by Region".
5. When a table beats a chart
If people need exact values, or there are many measures per item, use a well-formatted table with conditional formatting. Charts are for patterns.
Common mistakes
Choosing the chart first and looking for a message later. Using the default Excel chart for every question. Descriptive titles that make the reader work out the point.