# Loosemore–Hanby index

The **Loosemore–Hanby index** measures disproportionality of electorial systems. It computes the absolute difference between votes cast and seats obtained using the formula:^{[1]}

The index is named after John Loosemore and Victor J. Hanby, who first published the formula in 1971 in a paper entitled "The Theoretical Limits of Maximum Distortion: Some Analytic Expressions for Electoral Systems". Along with Douglas W. Rae's, the formula is one of the two most cited disproportinality indices.^{[2]} Whereas the Rae index measures the average deviation, the Loosemore–Hanby index measures the total deviation. Michael Gallagher used least squares to develop the Gallagher index, which takes a middle ground between the Rae and Loosemore–Hanby indices.^{[3]}

## Further reading

- Loosemore, John; Hanby, Victor J. (October 1971). "The Theoretical Limits of Maximum Distortion: Some Analytic Expressions for Electoral Systems".
*British Journal of Political Science*. Cambridge University Press.**1**(4): 467–477. JSTOR 193346.

## References

- ↑ Cortona et al. 1999, p. 45.
- ↑ Grofman 1999, p. 292.
- ↑ Lijphart & Grofman 2007, p. 85.

### Works cited

- Cortona, Pietro Grilli di; Manzi, Cecilia; Pennisi, Aline; Ricca, Federica; Simeone, Bruno (1999).
*Evaluation and Optimization of Electoral Systems*. SIAM. ISBN 978-0-89871-422-7. - Grofman, Bernard (1999).
*Elections in Japan, Korea, and Taiwan Under the Single Non-transferable Vote: The Comparative Study of an Embedded Institution*. University of Michigan Press. ISBN 0-472-10909-X. - Lijphart, Arend; Grofman, Bernard (2007).
*The Evolution of Electoral and Party Systems in the Nordic Countries*. Algora Publishing. ISBN 978-0-87586-168-5.