additional member system advantages and disadvantages

The additional member system (AMS) is a voting system that combines elements of both proportional representation and plurality/majoritarian systems. Understanding the advantages and disadvantages of this system is crucial for evaluating its effectiveness in promoting democracy and representation. This article delves into the various facets of the additional member system, highlighting its strengths and weaknesses.

Table about additional member system advantages and disadvantages:

Increased proportionalityPotential for voter confusion
Enhanced representationComplex ballot design
Minimal wasted votesLarge number of wasted votes
Encourages coalition buildingInequality of vote weight
Allows voters to choose between candidates and partiesPossible dominance of major parties


1. Increased proportionality

The additional member system ensures a fairer distribution of seats in a legislature compared to plurality/majoritarian systems. It allows for a closer reflection of the voting percentage, ensuring that parties receive seats in line with their support. This feature contributes to a more accurate representation of the electorate’s preferences.

2. Enhanced representation

With an additional member system, there are two types of representatives elected: those from single-member constituencies and those from party lists. This dual nature of representation broadens the diversity of voices in the legislature. It enables voters to have a say not only in terms of their local representatives but also in shaping the overall representation through party choices.

3. Minimal wasted votes

In comparison to plurality/majoritarian systems where most votes cast for losing candidates go to waste, the additional member system significantly reduces the number of wasted votes. While votes for losing candidates in single-member constituencies may not lead to direct representation, they can contribute to the allocation of party-list seats, ensuring that these votes still count towards representation.

4. Encourages coalition building

The additional member system often encourages political parties to form coalitions in order to secure a majority of seats. This stimulates cooperation, compromise, and consensus among different ideological factions. Coalitions formed in this system can lead to stable governance, as parties are motivated to work together to achieve shared goals.

5. Allows voters to choose between candidates and parties

In an additional member system, voters have the freedom to choose both a preferred candidate and a favored party. This flexibility empowers individuals to express nuanced preferences. They can select a candidate based on their local representation skills while also considering the party’s broader policies and goals. This enables voters to have a more comprehensive impact on the political landscape.


1. Potential for voter confusion

Due to the complexity of the additional member system, some voters may find it confusing and challenging to understand. The inclusion of both individual candidates and party lists on the ballot can make the voting process more intricate, leading to potential errors or unintended choices.

2. Complex ballot design

The design of the ballot for the additional member system can be more involved and convoluted compared to other voting systems. It requires careful formatting and clear instructions to minimize confusion and ensure voters can easily navigate the process. Failure to achieve simplicity in the ballot design may result in higher rates of spoiled or miscounted votes.

3. Large number of wasted votes

While the additional member system reduces wasted votes, it still carries the possibility of a significant number of votes not translating into seats. This waste can occur when smaller parties or independent candidates fail to gain enough support to secure seats in either single-member constituencies or party lists, leading to potentially underrepresented voices.

4. Inequality of vote weight

In some cases, the additional member system may lead to an imbalanced distribution of the overall vote weight. Due to differences in constituency sizes, the value of an individual’s vote may vary depending on their location. This can result in some voters having more influence than others, undermining the principle of equal representation.

5. Possible dominance of major parties

In certain instances, the additional member system can perpetuate the dominance of major parties. The winner-takes-all nature of single-member constituencies may favor larger and more established parties, making it challenging for smaller parties or independent candidates to gain significant representation. This could limit the diversity of political voices in the legislature.

Benefits of knowing the additional member system advantages and disadvantages:

Gaining insights into the advantages and disadvantages of the additional member system is essential for informed decision-making. It allows individuals, policymakers, and electoral reform advocates to evaluate the system’s appropriateness for their specific context. Understanding these pros and cons facilitates meaningful discussions, reforms, or potential modifications aimed at enhancing democratic representation.

The additional member system presents an intriguing alternative to traditional voting systems, incorporating both proportional representation and plurality/majoritarian features. While it offers increased proportionality, enhanced representation, and minimal wasted votes, it also poses challenges such as potential voter confusion, complex ballot design, and possible dominance of major parties. By acknowledging the system’s advantages and disadvantages, informed decisions can be made towards shaping more inclusive and effective democratic processes.