Learning Objectives
By the end of this lesson, learners should be able to:
- Match business questions with suitable chart types.
- Explain the strengths and weaknesses of common charts.
- Create comparison, trend, composition, and relationship charts.
- Avoid inappropriate chart selection.
Chart Selection Framework
The first step in visualization is identifying the analytical objective.
|
Business Question |
Recommended Chart |
|
Compare categories |
Bar/Column Chart |
|
Show trends over time |
Line Chart |
|
Show composition |
Stacked Bar / Pie (few categories) |
|
Show relationship between variables |
Scatter Plot |
|
Show distribution |
Histogram / Box Plot |
|
Show geographic variation |
Map |
Bar And Column Charts
Use For
- Comparing sales by country,
- Comparing profit by product,
- Comparing customer counts by segment.
International Example
A software company compares annual subscription revenue from United States, Canada, United Kingdom, Germany, and Singapore.
Bar charts make ranking easy to interpret.
Best Practices
- Sort values logically,
- Start the axis at zero,
- Limit categories where possible.
Line Charts
Use For
- Monthly sales trends,
- Website traffic over time,
- Quarterly profit trends.
Example
A global hotel chain tracks monthly occupancy rates across 24 months.
Line charts emphasize change over time.
Best Practices
- Use consistent time intervals,
- Avoid excessive markers,
- Highlight important events if relevant.
Pie And Donut Charts
Use For
Showing parts of a whole with fewer than five categories.
Example
Market share among four smartphone brands.
Limitations
- Difficult to compare similar slice sizes,
- Ineffective with many categories.
Use stacked bars instead when precise comparison is important.
Scatter Plots
Use For
Examining relationships between two quantitative variables.
Example
Advertising expenditure vs. sales revenue across 50 international markets.
Scatter plots reveal:
- Positive relationships,
- Negative relationships,
- Clusters,
- Outliers.
Histograms
Use For
Showing the distribution of continuous data.
Example
Distribution of delivery times for an international courier service.
Analysts can identify skewness and unusual patterns.
Box Plots
Use For
Comparing distributions across groups.
Example
Comparing employee salaries across offices in London, New York, and Singapore.
Box plots show median, quartiles, spread, and outliers.
Maps
Use For
Displaying geographic patterns.
Example
Revenue by country for a global consumer electronics company.
Caution
Maps should not be used when geographic location is not important.
Dual-Axis Charts
Use carefully when comparing variables with different units.
Example
Revenue (USD) and customer satisfaction (%) over time.
Ensure users understand both scales.
Small Multiples
Small multiples display several similar charts with the same scale.
Example
Monthly sales trends for each region shown in separate panels.
This supports easier comparison than overlapping many lines.
Common Chart Selection Errors
- Using pie charts for many categories,
- Using line charts for unordered categories,
- Using stacked charts when exact comparison is required,
- Using maps for non-geographic data,
- Using 3D charts for business reporting.
Case Study: Global Manufacturing Company
A manufacturing company presented production performance using a 3D pie chart with 12 factories. Managers struggled to identify differences.
Redesign
- Replaced with a sorted horizontal bar chart,
- Added target line,
- Used a single highlight color for underperforming factories.
Decision-making improved significantly.
Practical Exercise
Choose appropriate charts for:
- Quarterly revenue by region.
- Daily website traffic for one year.
- Profit contribution by product category.
- Relationship between training hours and productivity.
- Distribution of customer wait times.
Learning Materials / Reference Materials
- Few, S. Show Me the Numbers.
- Tableau Chart Selection Guide.
- Microsoft Power BI Visualization Documentation.
Lesson Summary
Selecting the correct chart type is essential for accurate communication. The chart should match the business question, support easy interpretation, and avoid misleading comparisons.