Evolution of Voting System

How voting system has evolved to provide better governance environment
The key of building successful DAO is fair governance system, and improved voting system can support it. From ‘one person one vote’, to ‘Quadratic Voting’, voting system has evolved to provide a better decision-making environment. PQV will create a new paradigm by making up for the shortcomings of existing methods.
source: Vitalik Buterin's Blog [4]

One Person, One Vote

source: Vitalik Buterin's Blog [4]
One person one vote is the voting system that individuals should have equal power in voting. This has made current democracy and most of the votes follow this principle.
However, one person one vote has a problem that people not interested or unrelated to the agenda also have the equal representation in voting. This can lead to another problem like ‘Tyranny of the majority’. Moreover, there is no way to express each individual’s eagerness in the vote, as same voting power is given to everyone without taking into account the circumstances of each voter.

One Dollar, One Vote

source: Vitalik Buterin's blog [4]
To solve the problem of one person one vote, one dollar one vote appeared as an alternative. Individuals who pay more can have more decision making power. People with high willingness to influence voting result can buy as many votes as possible. (at the same price per vote)
Voters deeply involved in the agenda can express their opinions strongly. However, this principle also has a weakness that the society could be ruled by a few strong individuals with enough assets to support their opinions.

Quadratic Voting (QV)

source: Vitalik Buterin's blog [4]
Quadratic voting can solve the problems of existing methods. In this principle, voters should pay
x2 x^2
to make
votes. In one dollar one vote, the cost of votes increased linearly. QV tried to refrain some individuals from exercising excessive influence by making the cost of voting increase exponentially.
To exercise 10 votes of voting power, people had to pay 10 under ‘one dollar one vote’ principle. But under QV, the cost increases rapidly and individuals should pay
Type of Votes
# of Votes
Cost of Votes
one person, one vote
1 (immutable)
one dollar, one vote
Quadratic Voting
In terms of voting methods, QV could be the mathematically optimal system, but it is exposed to risk called ‘Sybil attack’ that could undermine fairness of whole governance.