Calculator
Example Data Table
| Area | Group A | Group B | Purpose |
|---|---|---|---|
| Central District | 320 | 180 | Mixed core area |
| South District | 90 | 260 | High second-group concentration |
| Suburban Belt | 280 | 140 | Outer comparison zone |
| Old Town | 250 | 90 | High first-group concentration |
Formula Used
The calculator uses the common two-group segregation index, also called the index of dissimilarity in many demographic studies.
Formula:
D = 0.5 × Σ | Aᵢ / A - Bᵢ / B | × 100
Here, Aᵢ is the first group count in area i.
Bᵢ is the second group count in area i.
A and B are total counts for both groups across all areas.
A value near 0 means both groups follow similar spatial patterns.
A value near 100 means the groups are highly separated.
How to Use This Calculator
- Enter a report title and group labels.
- Add each area, ward, school, region, or unit.
- Enter the first and second group counts for every area.
- Choose decimal places for the final result.
- Click Calculate to view the index above the form.
- Use CSV or PDF buttons to download the report.
Understanding the Index of Segregation
What the Measure Shows
The index of segregation helps compare how two groups are distributed across several areas. It is often used in social research, housing studies, school analysis, employment review, and public planning. The method does not judge why a pattern exists. It only measures how uneven the distribution is.
Why Area Counts Matter
Each area contributes to the final score. A district with many people can affect the result strongly. A small district can also matter when its group mix is very different. That is why clean area data is important. You should use the same boundary system for every row.
Reading the Final Value
The result ranges from 0 to 100 percent. A score of 0 means both groups have identical area shares. A score of 100 means complete separation. Many real datasets fall between these limits. The calculator also shows an estimated rebalancing count. This count explains the index in practical terms.
Using Results Carefully
The index is useful for comparison. You can compare cities, years, schools, branches, or service regions. Still, it should not be used alone. Local history, policy, income, access, and geography can explain the pattern. Use the score as a starting point. Then review maps, tables, and local evidence.
Better Data Gives Better Insight
Use complete counts for both groups. Avoid mixing percentages and raw counts. Do not combine areas from different years unless that is your goal. Keep notes about data sources. This makes your report easier to audit. It also helps readers understand your conclusion.
FAQs
1. What is the index of segregation?
It measures how unevenly two groups are distributed across areas. A low score means similar distribution. A high score means stronger separation.
2. What does a zero score mean?
A zero score means both groups have the same area distribution. Each area holds the same share of both groups.
3. What does a score of 100 mean?
A score of 100 means complete separation. Each area contains only one group, with no overlap between the two groups.
4. Can I use percentages as inputs?
Raw counts are recommended. Percentages can distort totals unless every area uses the same base population and is prepared consistently.
5. How many areas should I enter?
Use at least two areas. More areas usually give a clearer view, especially when boundaries are meaningful and consistent.
6. Is this the same as the dissimilarity index?
For two-group distribution analysis, this formula is commonly treated as the index of dissimilarity or segregation.
7. What is the rebalancing estimate?
It estimates how many people from the smaller group would need redistribution for perfect evenness, based on the index value.
8. Can I export my results?
Yes. Use the CSV button for spreadsheet work. Use the PDF button for a compact printable report.