Effective Number of Parties (Laakso-Taagepera)

Calculate the effective number of parties N = 1/∑pᵢ² using Laakso and Taagepera's index, where pᵢ is each party's seat or vote share. Measures the fragmentation of a legislature or vote distribution.

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
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How It Works

Calculate the effective number of parties N = 1/∑pᵢ² using Laakso and Taagepera's index, where pᵢ is each party's seat or vote share. Measures the fragmentation of a legislature or vote distribution

Each component has a specific meaning:

  • Laakso — The laakso recorded for the scenario being assessed.
  • Taagepera's index — The taagepera's index recorded for the scenario being assessed.
  • Where pᵢ is each party's seat or vote share — The where pᵢ is each party's seat or vote share recorded for the scenario being assessed.

Note: Interpret the effective parties n result against the thresholds and context described above.

How to Use

Enter the Laakso, Taagepera's index, where pᵢ is each party's seat or vote share for the scenario you are assessing. Calculate the effective number of parties N = 1/∑pᵢ² using Laakso and Taagepera's index, where pᵢ is each party's seat or vote share. Measures the fragmentation of a legislature or vote distribution. Use the effective parties n result to inform your calculation.

Frequently Asked Questions