What does Simpson's D = 0.9 mean?

Simpson's D = 0.9 means if you randomly pick two individuals, there is a 90% probability they belong to different species/categories. Higher values indicate greater diversity. The complement (1-D) is sometimes called Simpson's dominance.

When is Simpson preferred over Shannon?

Simpson's index is less sensitive to rare species and more influenced by dominant species. It is preferred when community evenness matters more than total richness, and is more robust to sampling effort variation.

Simpson Diversity Index D Calculator

Calculate Simpson's diversity index D = 1 – ∑(nᵢ(nᵢ–1))/(N(N–1)), measuring the probability that two randomly selected individuals belong to different categories. Ranges 0 (no diversity) to 1 (infinite diversity).

Data set — comma or newline separated

Statistical Results — n = 8

Count (n)8

Sum (Σx)40

Min2

Max9

Range7

Q14

Q35.5

IQR1.5

Mean (μ)5

Median4.5

Mode4

Pop. Variance (σ²)4

Pop. Std Dev (σ)2

Sample Variance (s²)4.571428571

Sample Std Dev (s)2.138089935

Skewness0.65625

Excess Kurtosis-0.21875

How to Use

Enter the values for the scenario you are assessing. Calculate Simpson's diversity index D = 1 – ∑(nᵢ(nᵢ–1))/(N(N–1)), measuring the probability that two randomly selected individuals belong to different categories. Ranges 0 (no diversity) to 1 (infinite diversity). Use the simpson diversity d result to inform your calculation.

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Frequently Asked Questions

What does Simpson's D = 0.9 mean?

When is Simpson preferred over Shannon?