5 min read
Understanding Data Charts
Deep dive into understanding and creating data charts
Choosing the Right Chart
The right chart tells the right story!
Questions to Ask
-
What am I showing?
- Comparison → Bar chart
- Trend → Line chart
- Composition → Pie chart
- Distribution → Histogram
-
How many categories?
- Few (< 5) → Pie chart OK
- Many (> 5) → Use bar chart
-
Is it over time?
- Yes → Line chart
- No → Bar chart
Chart Types Explained
Bar Chart
- Shows comparison
- Horizontal or vertical
- Best for: Sales by category
Line Chart
- Shows change over time
- Connect points with lines
- Best for: Monthly sales trend
Pie Chart
- Shows parts of whole
- Use for few categories only
- Best for: Market share %
Histogram
- Shows distribution
- Groups numbers into bins
- Best for: Age distribution
Scatter Plot
- Shows relationship
- Two measures compared
- Best for: Sales vs Profit
Reading Charts
Bar Chart Reading
- Longer bar = Higher value
- Compare bar lengths
- Look at axis scale
Line Chart Reading
- Going up = Increasing
- Going down = Decreasing
- Flat = Stable
Pie Chart Reading
- Bigger slice = Larger portion
- Compare slice sizes
- Check percentages
Common Mistakes
| Mistake | Fix |
|---|---|
| Too many pie slices | Use bar chart |
| Wrong time scale | Adjust date level |
| Misleading axis | Start axis at 0 |
| Too many colors | Limit to 5-7 |
Best Practices
- Keep it simple
- Use clear titles
- Label important points
- Use consistent colors
- Don't distort data
Summary
Match chart type to your question. Bar for comparison, line for time, pie for parts. Keep it simple and clear!