Quadratic voting
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Quadratic voting (QV) is a voting system that encourages voters to express their true relative intensity of preference (utility) between multiple options or elections.[1] By doing so, quadratic voting seeks to mitigate tyranny of the majority—where minority preferences are by default repressed since under majority rule, majority cooperation is needed to make any change. Quadratic voting prevents this by allowing voters to vote multiple times on one option at the cost of not being able to vote as much on other options. This enables minority issues to be addressed where the minority has a sufficiently strong preference relative to the majority (since motivated minorities can vote multiple times) while also disincentivizing extremism or putting all votes on one issue (since additional votes require increasing sacrifice of influence over other issues).
In quadratic voting, voters allocate "credits" (usually distributed equally, though some suggest using real money) to various issues. The number of votes to add is determined by a quadratic cost function, which means that the number of votes a person casts for a given issue is equal to the square root of the number of credits they allocate (put another way, to add 3 votes requires allocating the square or quadratic of the number of votes, i.e., 9 credits).[2] Because the quadratic cost function makes each additional vote more expensive (to go from 2 votes to 3, you must allocate 5 extra credits, but to go from 3 to 4, you must add 7), voters are incentivized not to over-allocate to a single issue and instead to spread their credits across multiple issues to make better use of them. This creates voting outcomes more closely aligned with a voter's true relative expected utility between options. Compared to score voting or cumulative voting, where voters may simply not vote for any option other than their favorite, QV gives voters who more accurately represent their preferences across multiple options more overall votes than those who don't.[3]
| Number of votes |
"Vote credit" cost |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 16 |
| 5 | 25 |
Properties of quadratic voting
[edit]This section may need to be rewritten to comply with Wikipedia's quality standards. (January 2025) |
Efficiency
[edit]The quadratic cost function uniquely enables people to purchase votes in a way that reflects the strength of their preferences proportionally. As a result, the total votes cast on a given issue will correspond to the intensity of preferences among voters, effectively balancing the collective outcome according to both the direction and strength of individual preferences. This occurs because the marginal cost of each additional vote increases linearly with the number of votes cast. If the marginal cost increased less than linearly, someone who values the issue twice as much might buy disproportionately more votes, predisposing the system to favor intense special interests with concentrated preferences. This results in a "one-dollar-one-vote" dynamic, where marginal costs remain constant. Conversely, if the cost function rises faster than quadratically, it leads voters to limit themselves to a single vote, pushing the system toward majority rule where only the number of voters matters, rather than the intensity of preference.[1]
Quadratic voting is based upon market principles, where each voter is given a budget of vote credits that they have the personal decisions and delegation to spend in order to influence the outcome of a range of decisions. If a participant has a strong support for or against a specific decision, additional votes could be allocated to proportionally demonstrate the voter's support. A vote pricing rule determines the cost of additional votes, with each vote becoming increasingly more expensive. By increasing voter credit costs, this demonstrates an individual's support and interests toward the particular decision.[4]
By contrast, majority rule based on individual person voting has the potential to lead to focus on only the most popular policies, so smaller policies would not be placed on as much significance. The larger proportion of voters who vote for a policy even with lesser passion compared to the minority proportion of voters who have higher preferences in a less popular topic can lead to a reduction of aggregate welfare. In addition, the complicating structures of contemporary democracy with institutional self-checking (i.e., federalism, separation of powers) will continue to expand its policies, so quadratic voting is responsible for correcting any significant changes of one-person-one-vote policies.[5]
Robustness
[edit]Robustness of a voting system can be defined as how sensitive a voting scheme is to non-ideal behavior from either voters or outside influence. The robustness of QV with respect to various non-idealities has been studied, including collusion among voters, outside attacks on the voting process, and irrationality of the voters. Collusion is possible in most voting schemes to one extent or another, and what is key is the sensitivity of the voting scheme to collusion. It has been shown that QV exhibits similar sensitivity to collusion as one-person-one-vote systems, and is much less sensitive to collusion than the VCG or Groves and Ledyard mechanisms.[6] Proposals have been put forward to make QV more robust with respect to both collusion and outside attacks.[7] The effects of voter irrationality and misconceptions on QV results have been examined critically by QV by a number of authors. QV has been shown to be less sensitive to 'underdog effects' than one-person-one-vote.[6] When the election is not close, QV has also been shown to be efficient in the face of a number of deviations from perfectly rational behavior, including voters believing vote totals are signals in and of themselves, voters using their votes to express themselves personally, and voter belief that their votes are more pivotal than they actually are. Although such irrational behavior can cause inefficiency in closer elections, the efficiency gains through preference expression are often sufficient to make QV net beneficial compared to one-person-one-vote systems.[6] Some distortionary behaviors can occur for QV in small populations due to people stoking issues to get more return for themselves,[8] but this issue has not been shown to be a practical issue for larger populations. Due to QV allowing people to express preferences continuously, it has been proposed that QV may be more sensitive than one-person-one-vote to social movements that instill misconceptions or otherwise alter voters' behavior away from rationality in a coordinated manner.[9]
The quadratic nature of the voting suggests that a voter can use their votes more efficiently by spreading them across many issues. For example, a voter with a budget of 16 vote credits can apply 1 vote credit to each of the 16 issues. However, if the individual has a stronger passion or sentiment on an issue, they could allocate 4 votes, at the cost of 16 credits, to the singular issue, using up their entire budget.[10]
History of quadratic voting
[edit]One of the earliest known models idealizing quadratic voting was proposed by 3 scientists: William Vickrey, Edward H. Clarke, and Theodore Groves. Together they theorized the Vickrey–Clarke–Groves mechanism (VCG mechanism). The purpose of this mechanism was to find the balance between being a transparent, easy-to-understand function that the market could understand in addition to being able to calculate and charge the specific price of any resource. This balance could then theoretically act as motivation for users to not only honestly declare their utilities, but also charge them the correct price.[11] This theory was easily able to be applied into a voting system that could allow people to cast votes while presenting the intensity of their preference. However, much like the majority of the other voting systems proposed during this time, it proved to be too difficult to understand,[12] vulnerable to cheating, weak equilibria, and other impractical deficiencies.[13] As this concept continued developing, E. Glen Weyl, a Microsoft researcher, applied the concept to democratic politics and corporate governance and coining the phrase Quadratic Voting.[1][additional citation(s) needed]
The main motivation of Weyl to create a quadratic voting model was to combat against the "tyranny of the majority" outcome that is a direct result of the majority-rule model. He believed the two main problems of the majority-rule model are that it doesn't always advance the public good and it weakens democracy.[14] The stable majority has always been systematically benefited at the direct expense of minorities.[15] On the other hand, even hypothetically if the majority wasn't to be concentrated in a single group, tyranny of the majority would still exist because a social group will still be exploited. Therefore, Weyl concluded that this majority rule system will always cause social harm.[14] He also believed another reason is that the majority rule system weakens democracy. Historically, to discourage political participation of minorities, the majority doesn't hesitate to set legal or physical barriers. As a result, this success of a temporary election is causing democratic institutions to weaken around the world.[14]
To combat this, Weyl developed the quadratic voting model and its application to democratic politics. The model theoretically optimizes social welfare by allowing everyone the chance to vote equally on a proposal as well as giving the minority the opportunity to buy more votes to level out the playing field.[14]
Ideation in corporate governance
[edit]Quadratic voting in corporate governance is aimed to optimize corporate values through the use of a more fair voting system. Common issues with shareholder voting includes blocking out policies that may benefit the corporate value but don't benefit their shareholder value or having the majority commonly outvote the minority.[16] This poor corporate governance could easily contribute to detrimental financial crises.[17]
With quadratic voting, not only are shareholders stripped of their voting rights, but instead corporate employees can buy as many votes as they want and participate in electoral process. Using the quadratic voting model, one vote would be $1, while two votes would be $4, and so on. The collected money gets transferred to the treasury where it gets distributed to the shareholders. To combat voter fraud, the votes are confidential and collusion is illegal. With this, not only is the majority shareholders' power against the minority stripped, but with the participation of everyone, it ensures that the policies are made for the corporate's best interest instead of the shareholders' best interest.[16]
Payment
[edit]The most common objection to QV, are that if it uses real currency (as opposed to a uniformly distributed artificial currency) it efficiently selects the outcome for which the population has the highest willingness to pay. Willingness to pay, however, is not directly proportional to the utility gained by the voting population. For example, if those who are wealthy can afford to buy more votes relative to the rest of the population, this would distort voting outcomes to favor the wealthy in situations where voting is polarized on the basis of wealth.[4][18][Note 1]
Several alternative proposals have been put forward to counter this concern, with the most popular being QV with an artificial currency. Usually, the artificial currency is distributed on a uniform basis, thus giving every individual an equal say, but allowing individuals to more flexibly align their voting behavior with their preferences. While many have objected to QV with real currency, there has been fairly broad-based approval of QV with an artificial currency.[18][19][6]
Other proposed methods for ameliorating objections to the use of money in real currency QV are:
- To reduce or eliminate the unequal representation due to wealth, QV could be coupled with a scheme that returns incomes from the QV process to the less-wealthy. One such scheme is proposed to by Weyl and Posner.[2]
- For situations where issues are polarized based on wealth, one-person-one-vote may be a better alternative, depending on how gains in efficiency from preference expression balance with distortions due to wealth polarization. The use of QV vs one-person-one-vote could be determined on an issue-by-issue basis.[6]
- Votes could be made more expensive to wealthy voters either for all issues, or for issues which are polarized on the basis of wealth.[6]
Applications
[edit]United States
[edit]Many areas have been proposed for quadratic voting, including corporate governance in the private sector,[20] allocating budgets, cost-benefit analyses for public goods,[21] more accurate polling and sentiment data,[22] and elections and other democratic decisions.[5]
Quadratic voting was conducted in an experiment by the Democratic caucus of the Colorado House of Representatives in April 2019. Lawmakers used it to decide on their legislative priorities for the coming two years, selecting among 107 possible bills. Each member was given 100 virtual tokens that would allow them to put either 10 votes on one bill (as 100 virtual tokens represented 10 votes for one bill) or 5 votes each (25 virtual tokens) on 4 different bills. In the end, the winner was Senate Bill 85, the Equal Pay for Equal Work Act, with a total of 60 votes.[23] From this demonstration of quadratic voting, no representative spent all 100 tokens on a single bill, and there was delineation between the discussion topics that were the favorites and also-rans. The computer interface and systematic structure was contributed by Democracy Earth, which is an open-source liquid democracy platform to foster governmental transparency.[24]
Taiwan
[edit]The first use of quadratic voting in Taiwan was hosted by RadicalxChange in Taipei, where quadratic voting was used to vote in the Taiwanese presidential Hackathon.[25] The Hackathon projects revolved around 'Cooperative Plurality' – the concept of discovering the richness of diversity that is repressed through human cooperation.[26] Judges were given 99 points with 1 vote costing 1 point and 2 votes costing 4 points and so on. This stopped the follow-up effect and group influenced decision that happened with judges in previous years.[25] This event was considered a successful application of quadratic voting.
Germany
[edit]In Leipzig, Germany, Volt Germany – a pan-European party – held its second party congress and used quadratic voting to determine the most valued topics in their party manifesto among its members.[27] Partner with Deora, Leapdao, a technology start-up company, launched its quadratic voting software consisting of a "burner wallet". Since there was limited time and it was a closed environment, the "burner wallet" with a QR code acted as a private key that allowed congress to access their pre-funded wallet and a list of all the proposals on the voting platform.[28] The event was considered a success because it successfully generated a priority list that ranked the importance of the topics.
Quadratic voting also allowed researchers to analyze voter distributions. For example, the topic of Education showed especially high or emotional value to voters with the majority deciding to cast 4 or 9 voice-credits (2 or 3 votes) and a minority casting 25-49 voice-credits (5-7 votes).[28] On the other hand, the topic of Renewed Economy showed a more typical distribution with a majority of voters either not vote or max out at 9 voice-credits (3 votes). This indicates that there are less emotionally invested voters on this proposal as many of them didn't even spend tokens to vote on it.[28]
Brazil
[edit]In Brazil, the city council of Gramado has used quadratic voting to define priorities for the year and to reach consensus on tax amendments.[29]
Quadratic funding
[edit]Vitalik Buterin in collaboration with Zoë Hitzig and E. Glen Weyl proposed quadratic funding, a way to allocate the distribution of funds (for example, from a government's budget, a philanthropic source, or collected directly from participants) based on quadratic voting, noting that such a mechanism allows for optimal production of public goods without needing to be determined by a centralized legislature. Weyl argues that this fills a gap with traditional free markets – which encourage the production of goods and services for the benefit of individuals, but fail to create outcomes desirable to society as a whole – while still benefiting from the flexibility and diversity free markets have compared to many government programs.[30][31][32]
The Gitcoin Grants initiative is an early adopter of quadratic funding. However, this implementation differs in several ways from the original QF scheme.[33] Led by Kevin Owocki, Scott Moore, and Vivek Singh, the initiative has distributed more than $60,000,000 to over 3,000 open-source software development projects as of 2022.[34]
See also
[edit]Notes
[edit]- ^ More formally, willingness to pay is approximately the utility gain experienced by the individual voting normalized by the marginal utility of money. The marginal utility of money decreasing with increasing wealth, and therefore willingness to pay is inflated for wealthy individuals.
References
[edit]- ^ a b c Lalley, Steven; Weyl, E. Glen (24 December 2017). "Quadratic Voting: How Mechanism Design Can Radicalize Democracy". SSRN 2003531.
- ^ a b Posner, Eric A.; Weyl, E. Glen (2018). Radical markets: uprooting capitalism and democracy for a just society. Princeton University Press. ISBN 9780691177502. OCLC 1030268293.
- ^ Weyl, E. Glen (1 July 2017). "The robustness of quadratic voting". Public Choice. 172 (1): 75–107. doi:10.1007/s11127-017-0405-4. ISSN 1573-7101. S2CID 189841584.
- ^ a b Posner, Eric (30 December 2014). "Quadratic voting". ERIC POSNER. Retrieved 9 October 2019.
- ^ a b Weyl, Eric Glen; Posner, Eric A. (2014). "Voting Squared: Quadratic Voting in Democratic Politics". University of Chicago Law School Coase-Sandor Institute for Law and Economics.
- ^ a b c d e f Posner, Eric A.; Weyl, E. Glen (2017). "Quadratic voting and the public good: Introduction". Public Choice. 172 (1–2): 1–22. doi:10.1007/s11127-017-0404-5. S2CID 46616848.
- ^ Park, Sunoo; Rivest, Ronald L. (2017). "Towards secure quadratic voting". Public Choice. 172 (1–2): 151–175. doi:10.1007/s11127-017-0407-2. hdl:1721.1/110335. S2CID 5059331.
- ^ Patty, John W.; Penn, Elizabeth Maggie (2017). "Uncertainty, polarization, and proposal incentives under quadratic voting". Public Choice. 172 (1–2): 109–124. doi:10.1007/s11127-017-0406-3. S2CID 157943343.
- ^ Kaplow, Louis; Kominers, Scott Duke (2017). "Who will vote quadratically? Voter turnout and votes cast under quadratic voting". Public Choice. 172 (1–2): 125–149. doi:10.1007/s11127-017-0412-5. S2CID 157660093.
- ^ Hasen, Richard L. (2000). "Vote Buying". California Law Review. 88 (5): 1323–1371. doi:10.2307/3481262. ISSN 0008-1221. JSTOR 3481262.
- ^ Algorithmic game theory. Nisan, Noam. Cambridge: Cambridge University Press. 2007. ISBN 978-0-511-35572-1. OCLC 191726233.
{{cite book}}: CS1 maint: others (link) - ^ Ausubel, Lawrence M.; Milgrom, Paul (9 December 2005), Cramton, Peter; Shoham, Yoav; Steinberg, Richard (eds.), "The Lovely but Lonely Vickrey Auction", Combinatorial Auctions, The MIT Press, pp. 17–40, doi:10.7551/mitpress/9780262033428.003.0002, ISBN 978-0-262-03342-8, retrieved 5 October 2020
{{citation}}: CS1 maint: work parameter with ISBN (link) - ^ Rothkopf, Michael H. (April 2007). "Thirteen Reasons Why the Vickrey-Clarke-Groves Process Is Not Practical". Operations Research. 55 (2): 191–197. doi:10.1287/opre.1070.0384. ISSN 0030-364X.
- ^ a b c d Posner, Eric A. Voting squared : quadratic voting in democratic politics. OCLC 869561134.
- ^ Guinier, Lani (1994). The tyranny of the majority : fundamental fairness in representative democracy. New York: Free Press. ISBN 0-02-913169-3. OCLC 29751359.
- ^ a b Posner, Eric A. Quadratic voting as efficient corporate governance. OCLC 869012361.
- ^ Erkens, David H.; Hung, Mingyi; Matos, Pedro (April 2012). "Corporate governance in the 2007–2008 financial crisis: Evidence from financial institutions worldwide". Journal of Corporate Finance. 18 (2): 389–411. doi:10.1016/j.jcorpfin.2012.01.005.
- ^ a b Laurence, Ben; Sher, Itai (2017). "Ethical considerations on quadratic voting". Public Choice. 172 (1–2): 195–222. doi:10.1007/s11127-017-0413-4. S2CID 55808371.
- ^ Ober, Josiah (2017). "Equality, legitimacy, interests, and preferences: Historical notes on Quadratic Voting in a political context". Public Choice. 172 (1–2): 223–232. doi:10.1007/s11127-017-0409-0. S2CID 157745097.
- ^ Posner, Eric A.; Weyl, E. Glen. "Quadratic Voting as Efficient Corporate Governance". University of Chicago Law Review (University of Chicago Coase-Sandor Institute for Law & Economics Research Paper No. 643).
- ^ Masur, Jonathan S. (2017). "Quadratic voting as an input to cost-benefit analysis". Public Choice. 172 (1–2): 177–193. doi:10.1007/s11127-017-0408-1. S2CID 55731681.
- ^ Quarfoot, David; von Kohorn, Douglas; Slavin, Kevin; Sutherland, Rory; Goldstein, David; Konar, Ellen (2017). "Quadratic voting in the wild: Real people, real votes". Public Choice. 172 (1–2): 283–303. doi:10.1007/s11127-017-0416-1. S2CID 155832950.
- ^ "A New Way of Voting That Makes Zealotry Expensive". Bloomberg.com. May 2019. Retrieved 9 October 2019.
- ^ "Democracy Earth - Borderless governance". democracy.earth. Retrieved 20 November 2019.
- ^ a b Huang, Yahsin (2 October 2019). "Highlights from First RadicalxChange Taipei Meetup". Medium. Retrieved 6 October 2020.
- ^ Erichsen, Leon (31 May 2020). "GitxChange: Build the Roots of Cooperative Plurality". RadicalxChange. Retrieved 6 October 2020.
- ^ "The new voting system that could save our democracies". nesta. Retrieved 3 November 2020.
- ^ a b c "LeapDAO: delivering scalability as global public utility". leapdao.org. Retrieved 3 November 2020.
- ^ "The Mathematic Method that Could Offer a Fairer Way to Vote". The Economist.
- ^ Buterin, Vitalik. "Quadratic Payments: A Primer". Archived from the original on 23 May 2022. Retrieved 5 February 2020.
- ^ Buterin, Vitalik; Hitzig, Zoë; Weyl, E. Glen (2018). "Liberal Radicalism: A Flexible Design For Philanthropic Matching Funds". arXiv:1809.06421. doi:10.1287/mnsc.2019.3337. S2CID 198858039. SSRN 3243656.
{{cite journal}}: Cite journal requires|journal=(help) - ^ Weyl, Glen; Wiblen, Rob. "Glen Weyl on uprooting capitalism and democracy for a just society". 80,000 Hours Podcast.
- ^ Wildrick Thomas, Matthew (11 March 2021). "How to Fund Open Source".
- ^ "Gitcoin Grants Explorer". Gitcoin: Grow Open Source.
External links
[edit]- WTF is Quadratic Funding. Site by Gitcoin promoting quadratic funding. It includes a calculator.
Quadratic voting
View on GrokipediaCore Mechanism
Definition and Basic Operation
Quadratic voting is a decision-making procedure designed to elicit the intensity of participants' preferences over multiple options by imposing a quadratic cost on the number of votes purchased. Participants receive an endowment of voice credits, which serve as currency to buy votes on propositions, typically binary yes/no issues. The cost to acquire the k-th vote on any issue is k credits, resulting in a total expenditure of approximately k2/2 credits for k votes, though implementations may normalize this to k2 for simplicity.[8][9] This quadratic pricing structure increases the marginal cost of additional votes, incentivizing voters to concentrate credits on issues where their preferences are strongest while limiting influence on many weakly held views. Votes are tallied linearly across all participants, with the aggregate determining outcomes such as approval or ranking. For instance, in a system with N propositions and K credits per voter, strategic allocation reveals relative utilities, as the convex cost function aligns individual spending with preference gradients under equilibrium assumptions.[3] Basic operation often involves one-time or periodic credit distributions, with credits non-transferable between voters to prevent collusion, though variants allow refunds or multi-round adjustments. Propositions can span policy choices, resource allocation, or prioritization, where the mechanism contrasts with one-person-one-vote systems by amplifying minority intensities without unbounded voice. Empirical pilots, such as those in corporate governance or community forums, demonstrate feasibility, with software handling credit deductions and vote aggregation in real-time.[10][11]Mathematical Formulation and Variants
In the canonical formulation of quadratic voting (QV) for a binary collective decision, as developed by Lalley and Weyl, a population of voters each endowed with one unit of voice credits faces a choice between two alternatives, say A or B. Each voter privately values alternative A over B by , drawn independently from a symmetric distribution around zero. Voter purchases votes in favor of their preferred alternative, incurring a cost of credits paid to a central clearinghouse. The alternative receiving the greater total votes () is selected; ties are resolved randomly.[3][12] Under the assumption of quasilinear utility (), the game possesses a unique symmetric Bayes-Nash equilibrium in large electorates. Voters act as price-takers, purchasing votes up to the point where the marginal cost equals the expected marginal benefit, yielding total votes approximately equal to the expected absolute aggregate value . This price converges to the competitive equilibrium price as , rendering the mechanism asymptotically efficient and strategyproof in expectation, as deviations yield negligible pivotality.[12][8] Variants extend this framework. In multi-issue QV, voters allocate a fixed budget across independent binary decisions, purchasing votes for issue at cost , with . Equilibrium strategies reveal relative intensities, with credits flowing to issues of highest private value density, preserving approximate efficiency under separability.[7] Fixed-budget QV imposes a global expenditure cap per voter while allowing variable vote supply, contrasting with the endowment-based clearinghouse model; Posner and Weyl analyze its application to corporate governance, where quadratic costs mitigate logrolling incentives.[4] Multiple-alternatives QV generalizes to options via pairwise or bundled bidding, where voters buy votes against a status quo or across contests, maintaining quadratic marginal costs to approximate utilitarian welfare; Eguia et al. prove convergence to efficient randomized social choice rules in large populations.[13]Theoretical Foundations
Claims of Efficiency
Proponents claim that quadratic voting achieves greater efficiency in aggregating preferences by enabling voters to express the intensity of their utilities through differentially priced votes, where the cost of each additional vote increases quadratically. This structure discourages over-voting on low-intensity issues and concentrates influence on matters of high personal stakes, theoretically leading to outcomes that more closely maximize aggregate social welfare than linear voting systems, which ignore preference strengths.[14] In theoretical models, the quadratic cost function aligns individual incentives with truthful revelation of valuations, as voters optimally allocate limited credits to proposals proportional to the square root of their utility differences, resulting in collective signals that approximate efficient resource allocation. For instance, Posner and Weyl argue that in corporate governance contexts, this mechanism outperforms traditional share-weighted voting by allowing dispersed shareholders with intense preferences—such as on executive compensation or mergers—to override apathetic majorities, thereby enhancing firm value maximization. Empirical simulations and equilibrium analyses support that such efficiency holds under assumptions of rational, budget-constrained agents without collusion.[4][2] Further claims posit that quadratic voting's efficiency extends to public decision-making, where it mitigates the inefficiencies of majority rule in handling heterogeneous intensities, such as protecting minority interests with high stakes. Lalley and Weyl's analysis demonstrates that in large populations, the mechanism's Nash equilibrium converges rapidly to the socially optimal decision, leveraging asymptotic properties akin to market clearing for public goods. This convergence relies on voters' strategic behavior, which, unlike in linear systems, can enhance rather than undermine efficiency by amplifying signals from informed participants. However, these efficiency claims presuppose sufficient credits, no externalities in vote purchases, and voters' ability to accurately assess their utilities, conditions that may not hold in practice.[15][16]Assertions of Robustness
Proponents of quadratic voting assert that the mechanism exhibits approximate strategy-proofness in large electorates, where voters' optimal strategy converges to revealing their true preference intensities. In a model where voters' utilities are independently drawn from a known distribution and the number of participants approaches infinity, Lalley and Weyl demonstrate that the unique symmetric Bayes-Nash equilibrium involves each voter purchasing a number of votes equal to the absolute value of their private utility for the binary decision, rendering deviations from truth-telling unprofitable in expectation.[17] This equilibrium arises because the quadratic pricing—where the cost of the v-th vote equals v credits—approximates a competitive market equilibrium, aligning individual incentives with efficient aggregation of intensities without requiring dominant-strategy incentives.[12] The system is further claimed to be robust to collusion by small subgroups, as the quadratic cost structure limits the amplifying effect of coordinated behavior. Spencer analyzes an equilibrium model of QV with colluding minorities, using heuristic approximations to quantify that a subgroup comprising a fraction of the electorate can at best distort the outcome by an amount on the order of , rather than linearly in as in one-person-one-vote systems. For instance, in electorates of size n exceeding 10,000, collusions involving fewer than participants yield negligible influence, as pooling fixed per-person voice credits incurs rapidly escalating marginal costs that deter over-investment beyond the group's proportionate stake. This property stems from the convexity of the cost function, which penalizes disproportionate vote concentration more severely than linear mechanisms. Additional robustness assertions highlight resistance to certain forms of vote-buying or external manipulation, provided voice credits are non-transferable and tied to verified identities. Unlike cash-based vote trading, the internal currency of credits prevents monetary corruption from directly scaling influence, as each participant's budget remains capped and quadratically constrained.[8] However, these claims hold under idealized assumptions of independent utilities and no large-scale coordination; vulnerabilities emerge if a majority colludes or if sybil attacks inflate participant counts, though proponents argue real-world identity verification mitigates the latter. Empirical analogs in controlled experiments, such as those comparing QV to plurality voting, support reduced strategic abstention, with participants expressing intensities more consistently across issues.[18]Equilibrium Analysis
In quadratic voting mechanisms for binary decisions, equilibrium analysis models voter behavior as a Bayesian game where each of N agents possesses a private valuation drawn independently from a smooth distribution with bounded support and positive density, representing the utility from the preferred outcome. Voters allocate a budget to purchase votes at quadratic cost , aiming to maximize expected utility , where aggregates opponents' net votes and is a smooth, increasing function capturing outcome probabilities.[12] Pure-strategy Nash equilibria exist and are monotone increasing in valuations for , under standard conditions including compactly supported with derivative bounded away from extremes. In symmetric equilibria, moderate voters purchase votes approximately linearly in their valuations, scaled by a factor converging to zero as , reflecting strategic attenuation due to pivotal probabilities shrinking with electorate size.[12] For balanced electorates where the mean valuation , equilibria are continuous, and strategies approximate myopic revelation adjusted for aggregate uncertainty, yielding asymptotic efficiency: expected inefficiency, measured as welfare loss relative to full information optima, vanishes as for any bounded distribution . When , equilibria exhibit discontinuities in the tails, where extremists purchase disproportionately many votes—scaling linearly with —to insure against moderate opponents, yet efficiency still holds asymptotically, with inefficiency decaying as .[12] Multiple equilibria can arise from self-fulfilling discontinuities, particularly in unbalanced settings, allowing inefficient outcomes like uniform abstention or coordination on suboptimal sides if voters share correlated beliefs; however, symmetric equilibria are conjectured unique except at isolated points, and robustness analyses indicate low vulnerability to collusion or fraud in large populations, with empirical inefficiencies rarely exceeding 10%. These properties stem from quadratic costs internalizing externalities akin to market pricing, though deviations from exact truth-telling persist due to interdependent pivotalities.[12]Historical Development
Precursors and Early Ideas
The concept of quadratic voting emerged from broader traditions in mechanism design theory, which seeks to create incentive-compatible rules for eliciting truthful preferences in collective decisions. Foundational work includes William Vickrey's 1961 proposal for second-price auctions, where bidders reveal true valuations by paying the second-highest bid if they win, establishing principles of truthful revelation without strategic misrepresentation. This approach influenced subsequent developments in social choice, emphasizing costs or payments to align individual incentives with efficient outcomes.[19] Further precursors lie in the Vickrey-Clarke-Groves (VCG) mechanism, articulated by Edward Clarke in 1971 and Theodore Groves in 1973, which generalizes Vickrey's ideas to public goods provision. In VCG, agents report valuations, and payments equal the externality imposed on others, often resulting in quadratic-like terms when utilities exhibit diminishing marginal returns or in multi-agent settings. These mechanisms aimed to achieve Pareto efficiency by making truth-telling a dominant strategy, though they faced practical challenges like high informational demands and budget imbalances—issues quadratic voting later addresses through symmetric, credit-based quadratic costs. Early mechanism design thus provided the theoretical scaffolding for incorporating preference intensities via convex pricing, contrasting with traditional voting's equal-weight aggregation that disregards varying stakes.[20] The immediate early ideas for quadratic voting proper trace to E. Glen Weyl's working paper circulated in February 2012, initially titled "Quadratic Vote Buying." This explored voters purchasing additional votes at a quadratic cost in voice credits, arguing it incentivizes proportional expression of intensity while preventing dominance by intense minorities through escalating marginal costs.[8] Weyl demonstrated equilibrium existence and efficiency properties for convex (including quadratic) cost functions, building directly on mechanism design to mitigate issues like the tyranny of the minority in one-person-one-vote systems. This formulation predated broader dissemination, serving as the conceptual seed later refined for democratic and governance applications.[2]Formal Introduction and Key Publications
Quadratic voting was formally introduced by economist E. Glen Weyl in a working paper circulated in February 2012, initially titled "Quadratic Vote Buying," which proposed the mechanism as a method for voters to purchase additional votes at a quadratic cost to better reflect preference intensities in collective decision-making.[2] The paper formalized the core idea using game-theoretic equilibrium analysis, demonstrating that under quadratic pricing, voters reveal truthful marginal valuations, leading to efficient aggregation akin to market outcomes.[2] Weyl's framework addressed limitations of one-person-one-vote systems by allowing differential vote expenditures proportional to squared quantities, with credits distributed equally or based on stakes, and emphasized applications beyond politics, such as corporate governance.[4] Subsequent key publications expanded and refined the concept for democratic contexts. In 2015, Eric A. Posner and Weyl published "Voting Squared: Quadratic Voting in Democratic Politics" in the Vanderbilt Law Review, adapting the mechanism for legislative and electoral use, where voters receive voice credits to buy votes on bills or candidates, with costs rising quadratically to prevent majority dominance over intense minorities.[21] This work argued for quadratic voting's superiority in balancing fairness and efficiency, supported by simulations showing reduced strategic abstention compared to linear voting.[21] Posner and Nicholas O. Stephanopoulos further developed electoral applications in their 2016 paper "Quadratic Election Law," proposing district-level implementations to mitigate gerrymandering and enhance representation of varied intensities.[22] Theoretical advancements continued with Steven P. Lalley and Weyl's 2018 contribution, "Quadratic Voting: How Mechanism Design Can Radicalize Democracy," presented at the American Economic Association, which provided mechanism design proofs for incentive compatibility under incomplete information and large electorates, confirming convergence to efficient social welfare maximization.[3] These publications collectively established quadratic voting's foundations, influencing subsequent empirical trials and variants, though early works like Weyl's focused more on abstract efficiency than practical robustness critiques.[23]Theoretical Refinements
Following the initial formulation of quadratic voting by Posner and Weyl in 2015, subsequent theoretical work focused on establishing the existence and properties of equilibria. In a 2019 analysis, Lalley and Weyl demonstrated that quadratic voting admits approximate Bayesian Nash equilibria where voters reveal their true intensities truthfully in expectation, particularly as the electorate size grows large; this result relies on voters having quasilinear preferences and facing proposals with binary outcomes, with strategic deviations becoming negligible due to the quadratic cost structure aggregating signals efficiently.[24] This refinement addressed early concerns about manipulability by showing convergence to the utilitarian optimum under mild conditions, though it assumes common priors on proposal values.[24] Weyl further refined the theory in 2017 by examining robustness to deviations from ideal assumptions, such as partial collusion among voters or non-quasilinear utilities. Using heuristic approximations, he proved that quadratic voting maintains near-optimal efficiency even when up to a constant fraction of voters collude or when preferences exhibit moderate risk aversion, as the mechanism's signal aggregation dampens strategic noise more effectively than linear voting.[25] These results hold for electorates exceeding hundreds of participants, with welfare losses bounded by factors independent of scale, contrasting with one-person-one-vote systems that amplify minority suppression under similar perturbations. Extensions to multi-issue and multi-alternative settings emerged around 2019, with Lalley and Weyl analyzing quadratic voting over multiple binary proposals under fixed budgets. They established that truthful equilibria persist when issues are independent, but interdependence introduces approximation guarantees rather than exact truthfulness, with efficiency approaching the optimum as budgets allow flexible allocation across issues.[13] Posner and Stephanopoulos complemented this in 2017 by formalizing fixed-budget variants, proving incentive compatibility for discrete vote allocations while preserving intensity expression, though at the cost of minor distortions in large-budget limits.[26] These developments highlighted trade-offs, such as reduced robustness to correlated preferences in multi-dimensional spaces, prompting further equilibrium refinements under asymmetric information.[27]Practical Implementations
Political and Governmental Trials
One of the earliest governmental trials of quadratic voting occurred in the Democratic caucus of the Colorado House of Representatives in April 2019, involving 41 members who each received 100 voice credits to allocate across approximately 60 to 100 appropriations bills.[28] Participants purchased votes quadratically, with costs escalating as the square of votes cast for any option, in an anonymous, non-binding poll to signal funding priorities amid a $40 million allocation for over $120 million in requests.[29] The process highlighted strong support for initiatives like Senate Bill 85 on equal pay, which garnered 60 votes, while producing a "long tail" of lower-priority items, enabling clearer prioritization than traditional methods.[28] Subsequent iterations expanded the trial's scope in Colorado. In June 2020, executive branch interagency groups used quadratic voting to rank goals, contributing to the creation of a new Behavioral Health Administration, though some outcomes were not adopted by the governor's office.[30] From 2021 to 2023, both Democratic and Republican caucuses in the state House and Senate employed the mechanism—often via RadicalxChange tools or spreadsheets—for legislative polls on over 80 bills and appropriations, describing it as a tool for nuanced preference revelation in resource-constrained settings.[30] In Spring 2023, quadratic voting was applied to participatory budgeting in New York City's Harlem District 9 by former Council Member Kristin Richardson Jordan, using an online platform with voter-roll verification and QR code authentication for residents.[31] Participants allocated credits across spending proposals, with guides and videos aiding engagement; the top outcome funded "The Baxter" affordable housing project with $1 million after receiving 136 votes, alongside an 80% satisfaction rate among voters, though 18% did not exhaust their budgets.[31] Nashville implemented quadratic voting for its 2023 county budget process through an online tool, as part of Mayor John Cooper's participatory budgeting pilot, which had previously engaged 500 residents in generating 400 project ideas for potential $20 million expansion.[32] Supported by Metro Council member Burkley Allen and enabled by state legislation from Governor Bill Lee recognizing decentralized decision-making, the trial aimed to prioritize broadly supported needs using voice credits.[32] Jersey City, under Mayor Steven Fulop, incorporated similar mechanisms into participatory budgeting for community projects like playgrounds and arts funding, allocating $900,000 across 89 recipients in 2020, though specifics on quadratic cost structures were integrated into broader engagement efforts.[32] These trials have remained small-scale and advisory, focusing on budget prioritization rather than binding decisions, with implementations often relying on third-party software amid concerns over software reliability in early adopters like Colorado's Senate Democrats.[29]Corporate and Private Sector Uses
In corporate governance, quadratic voting has been proposed as a mechanism to enhance shareholder decision-making by allowing investors to allocate votes quadratically based on the intensity of their preferences, addressing limitations of traditional one-share-one-vote systems where dispersed ownership leads to apathy and managerial opportunism. Eric Posner and E. Glen Weyl argued in a 2014 paper that quadratic voting could achieve efficient outcomes in shareholder votes on issues like mergers or executive compensation by enabling minority shareholders with strong views to amplify their influence without requiring proportional ownership, thus reducing agency costs identified since Berle and Means's 1932 analysis.[4][33] Theoretical models suggest quadratic voting promotes collective efficiency in corporate decisions, as shareholders rationally allocate limited voice credits to maximize utility, converging on outcomes aligned with the median intensity-weighted preference under large electorates. A 2024 study comparing quadratic voting to majority voting in shareholder contexts found that, assuming collective rationality, both systems yield efficient firm decisions, but quadratic voting better captures preference intensities, potentially improving resolutions on complex proposals like bylaw amendments.[34] However, implementation remains largely theoretical, with no widespread adoption in public companies as of 2025, due to regulatory hurdles under securities laws and challenges in verifying vote credits without collusion risks. In private sector applications beyond public firms, quadratic voting has been explored for internal decision processes, such as product prioritization or resource allocation in tech firms and investment portfolios. For instance, analyses have applied it to portfolio planning, where stakeholders use quadratic credits to signal strong convictions on asset selections, theoretically outperforming linear voting by weighting passion over mere headcount. Blockchain-based private organizations, including decentralized autonomous organizations (DAOs) in venture funding, have piloted quadratic voting for governance proposals, enabling token holders to express vote intensities on protocol upgrades, though empirical scalability issues persist.[35] These uses highlight quadratic voting's potential to democratize private decision-making while preserving efficiency, but real-world deployments are limited to experimental or niche settings, often integrated with cryptographic tools for anonymity and refund mechanisms.Digital and Decentralized Applications
Quadratic voting has been implemented in digital platforms to facilitate preference aggregation in online communities and organizations, often through web-based interfaces that allow users to allocate voice credits via quadratic costs. For instance, software tools developed by organizations like RadicalxChange enable experimental quadratic voting in digital settings, where participants purchase votes using predefined credits, with costs scaling quadratically to reflect intensity without requiring physical assembly.[11] These digital applications extend to non-blockchain environments, such as corporate decision-making tools, but gain prominence in decentralized contexts for their compatibility with pseudonymous participation. In decentralized autonomous organizations (DAOs) on blockchain networks, quadratic voting addresses governance challenges posed by token concentration, where large holders (whales) could dominate linear voting systems. By treating token stakes or allocated credits as quadratic budgets, it empowers minority voices and reduces plutocratic tendencies, as the marginal cost of additional votes rises quadratically.[36] This mechanism has been proposed and partially adopted in proof-of-stake (PoS) blockchains, where validators' stakes serve as vote budgets, promoting broader consensus on protocol upgrades or fund allocations.[37] Empirical analysis in DAOs shows quadratic voting variants improving decentralization metrics, though adoption remains limited due to computational overhead in smart contract execution.[38] Specific decentralized implementations include the Quadratic Voting Plugin in Realms, a Solana-based DAO governance platform launched in early 2025, which tempers the influence of high-stake voters by enforcing quadratic pricing on vote allocations for proposals.[39] Similarly, protocols like QV-net, introduced in June 2025, enable self-tallying quadratic voting on blockchains with maximal ballot secrecy, allowing public verification of results post-voting without revealing individual preferences during the process.[40] These systems leverage smart contracts for automated enforcement, as seen in experimental DAO elections where quadratic rules mitigate collusion risks compared to one-token-one-vote models.[41] However, challenges persist, including scalability on high-throughput chains and resistance to sybil attacks via identity verification layers.[42]Related Concepts
Quadratic Funding Mechanics
Quadratic funding allocates a fixed matching pool $ M $ to multiple public goods projects based on private donations, prioritizing projects with broad donor support over those funded by few large contributors.[43] The mechanism computes a subsidy for each project $ j $ by first determining a "voice" value $ v_j = \sum_{i \in D_j} \sqrt{c_{ij}} $, where $ D_j $ is the set of donors to project $ j $ and $ c_{ij} $ is the contribution from donor $ i $ to $ j $.[44] The target total funding for the project is then $ t_j = v_j^2 $, representing the quadratic aggregation of supporter intensities.[43] The raw subsidy is $ s_j = \max(0, t_j - p_j) $, where $ p_j = \sum_{i \in D_j} c_{ij} $ is the total private funding received by $ j $. To fit within $ M $, subsidies are scaled proportionally: final subsidy $ f_j = s_j \cdot \frac{M}{\sum_k s_k} $ if $ \sum_k s_k > M $, or $ f_j = s_j $ otherwise.[44] This formula derives from a model where the public funder seeks to maximize social welfare under assumptions of additive utility across projects and unit-elastic private marginal valuations, effectively treating small donations as signals of diverse support.[43] For instance, if 100 donors each contribute $1 to a project, $ v_j = 100 \times 1 = 100 $, so $ t_j = 10,000 $; with $ p_j = 100 $, the raw subsidy is $9,900, which would be scaled based on competing projects and $ M $. In contrast, a single $100 donation yields $ v_j = 10 $, $ t_j = 100 $, and raw subsidy $0, illustrating amplification of diffuse participation.[44] The approach assumes verifiable identities to prevent sybil attacks and infinitesimal contributions for continuous approximation, though practical variants cap contributions or use discrete adjustments.[43] Variations include pairwise quadratic funding, which bounds interactions between donor pairs to mitigate collusion, computing subsidies as $ M \times \frac{\sum_{i < k \in D_j} \min(\sqrt{c_{ij}}, \sqrt{c_{kj}})^2}{\sum_l \sum_{i < k \in D_l} \min(\sqrt{c_{il}}, \sqrt{c_{kl}})^2} $ or approximations thereof.[44] Minimum matching requirements can be imposed, where projects must exceed a private funding threshold to qualify, ensuring genuine interest before subsidy allocation.[45] These mechanics extend quadratic voting principles to funding by subsidizing contributions as if the pool were simulating collective decision-making with quadratic costs.[43]Distinctions from Quadratic Voting
Quadratic funding mechanisms, though inspired by similar quadratic principles, diverge from quadratic voting in their core objectives and operational frameworks. Quadratic voting aims to facilitate collective decision-making on predefined options, such as policy choices or platform planks, by enabling voters to express preference intensities through a budget of voice credits where the cost of casting the k-th vote on an option scales quadratically (k2 total credits for k votes), while the outcome tally aggregates votes linearly to balance minority passions against majority sentiments.[8] In contrast, quadratic funding targets the provision of public goods, like open-source software, by subsidizing projects with matching grants calculated as the square of the sum of square roots of individual donor contributions, thereby prioritizing broad-based support from many small donors over concentrated funding from few large ones to mitigate free-rider problems.[46] Mechanistically, quadratic voting imposes quadratic costs on voters' limited, equalized credit endowments to discourage frivolous spending and reveal true valuations across competing discrete alternatives, often within a fixed ballot or agenda.[2] Quadratic funding, however, leverages donors' voluntary monetary inputs without personal credit budgets, drawing from an external subsidy pool to amplify collective contributions dynamically; this allows for continuous, endogenous project emergence rather than voter-imposed selection among static options.[44] The former thus serves binary or ranked-choice scenarios in governance, as trialed in the Colorado Democratic Party's 2018 platform development, while the latter supports ongoing resource allocation, exemplified by Gitcoin's grants rounds starting in 2019 for Ethereum ecosystem projects.[11]| Aspect | Quadratic Voting | Quadratic Funding |
|---|---|---|
| Primary Purpose | Aggregating intensities for decisions on discrete options (e.g., approve/reject policies) | Allocating subsidies for continuous public goods provision (e.g., funding multiple initiatives) |
| Input Mechanism | Fixed credits per voter; quadratic cost to express k votes | Donor-chosen contributions; subsidy as (∑√ci)2 where ci are inputs |
| Output Type | Winner-take-all or ranked outcomes based on linear vote sums | Proportional matching grants favoring donor diversity |
| Constraints | Predefined agenda; equal starting budgets | No fixed options; relies on subsidy pool availability |
| Key Theoretical Basis | Optimizes utilitarian welfare under preference intensity (Lalley-Weyl, 2015)[8] | Addresses under-provision of public goods via matching (Buterin-Hitzig-Weyl, 2018)[46] |
