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Analysis of the effects of the Electoral Amendment Bill

14 February 2024

This paper presents the findings of an analysis of the Electoral Amendment Bill 2 and the claim that the Bill violates section 46 of the Constitution, demanding that the electoral system “results, in general, in proportional representation”.

Dr Halfdan Lynge (WSG Senior lecturer) and Simon Rosen (Graduate Student, School of Computer Science and Applied Mathematics) wrote this paper.

A preliminary analysis, of the Electoral Amendment Bill, submitted to the Electoral
Commission in September 2022, concluded that the claim is “based on a binary conception of proportionality, which deviates from political science theory and the South African Constitution” and “fails to recognise that the South African electoral system remains one of the most proportional in the world, having no electoral threshold and a large average district magnitude, and using one of the most proportional electoral formulae (Droop)”.

The preliminary analysis also recommended that “further analysis is done, […] using Monte Carlo simulations”.

The paper responds to the request for further analysis. It draws on hundreds of thousands simulations, representing hundreds of thousands hypothetical elections, and compares the seat allocation under the existing electoral formula (hereafter referred to as the ‘original electoral formula’) with the seat allocation under the electoral formula described in the Electoral Amendment Bill (hereafter referred to as the ‘amended electoral formula’).

In short, the paper finds that (1) the amended electoral formula does not introduce additional disproportionality; (2) deviation from perfect proportionality can be attributed to rounding error; and (3) the amended electoral formula contains a predisposition towards political parties with larger vote shares, but it is a predisposition that is inherited from the original electoral formula. Overall, our view therefore is that the Electoral Amendment Bill does not violate the constitutional demand that the electoral system results in proportional representation.

Read the full paper.