Electoral Formula and the Tunisian Constituent Assembly

1. Electoral Formula and the Tunisian Constituent Assembly John M. Carey Department of Government Dartmouth College USA

2. Tunisia’s October 2011 Election • 217 seats • 33 districts • 27 in Tunisia • 6 for expatriate voters • Ennahda predominated, but did not win majority. • Questions • Would the 2011 outcome have been different under other formulas? • What formula should Tunisia use in future elections?

3. Things Tunisia’s Electoral Engineers Did Right • Single-tier, single-vote system • List proportional representation (PR) • Moderate district magnitudes (DM)

4. The distribution of DM across districts in Tunisia’s 2011 election.

6. Number of districts in which alliances competed. Excluding lists that competed in only 1 district

7. 2 Families of PR Formulas Quota & Remainders Full Price • Q = Votes/DM (Hare) • Q = Votes/(DM+1) (Droop) • Q = Votes/(DM+2) (Low) Reduced Price • Seats “purchased” by Remainders Divisors Matrix of quotients • 1, 2, 3, 4, … (d’Hondt) • 1, 3, 5, 7, … (St. Lague) • 1, 4, 7, 10, … (Wentworth) • No dual pricing system

8. Illustration of Hare Quota & Remainders method in a hypothetical districtDM = 5 Total Votes = 1,000 Hare Quota = 200 [Votes/DM] • Distribution of seats by full Hare Quota • List A = 2 (Remainder = 15) • List B = 1 (Remainder = 125) • Total Seats • A = 2 • B = 2 • C = 1 • Distribution of 2 seats by Remainder • List C = 1 (Remainder = 185) • List B = 1 (Remainder = 125)

9. Hare Quota & Remainders DM = 10 Total Votes = 1,000 Hare Quota = 100 [Votes/DM] • Distribution of seats by full Hare Quota • List A = 4 (Remainder = 15) • List B = 3 (Remainder = 25) • List C = 1 (Remainder = 85) • Total Seats • A = 4 • B = 3 • C = 2 • D= 1 • Distribution of 2 seats by Remainder • List C = 1 (Remainder = 85) • List D = 1 (Remainder = 75)

10. Illustration of the D’Hondtmethod in a hypothetical district

11. DM=5

12. DM=10

14. How would the 2011 outcome have been different under other formulas? Method • Using district-level data from the Independent Higher Authority of the Election (ISIE): http://www.isie.tn/Ar/%D8%A7%D9%84%D8%B5%D9%81%D8%AD%D8%A9-%D8%A7%D9%84%D8%B1%D8%A6%D9%8A%D8%B3%D9%8A%D8%A9_46_3 Simulate outcomes under • Quota & Remainders systems (Hare, Droop, Low); and • Divisor systems (D’Hondt, St. Lague, Wentworth) • Party/List Seat Bonuses %Seats - %Votes … based on national vote share.

15. Are simulated results informative? Would both voters and elites behaved the same way under alternative PR formulas? Ballot paper

19. Are the differences among formulas always so dramatic? • No • General tendencies: • D’Hondt Divisor most favors large parties • Hare Quota & Remainders least favors large parties • But in most environments, the difference between formulas is modest.

20. Seat bonus by vote share for the most recent parliamentary elections in 12 countries (4 HQ-LR, 8 D’HD) that elect their lower chambers by list PR.

21. Seat bonus by vote share in Tunisia’s 2011 Constituent Assembly election, by various PR formulas.

22. What made Tunisia exceptional in 2011? • Moderate DM • 83% of seats allocated in districts with DM = 5-9 • Structure of Competition • 1 Big (Ennahda) and Many Little • Result under Quota & Remainders System • Only Ennahda won seats with full quotas • Other lists won almost all seats by remainders

23. Retail vs. Wholesale by Various Q&R Formulas

24. Seats by full quota vs remainders under 3 Q&R formulas

25. What will happen next? Prediction • The number of lists, and the fragmentation of the vote, will decline. • But the current formula creates incentives for small alliances that can compete for Remainder seats notto coalesce. • So maintaining Hare Quota & Remainders could present an obstacle to consolidation of the Tunisian party system. • Divisors formulas • Can be adjusted to be as inclusive as Q&R formulas. • Do not establish two-tier pricing – no incentives to hunt Remainders! • Reward broad coalitions.