Editing Public good (section)

=== Quadratic funding ===

Quadratic funding (QF) is one of the newest innovations in public goods funding mechanisms. The idea of [[Quadratic voting]] was turned into a mechanism for public goods funding by Buterin, Hitzig, and Weyl <ref>{{Cite journal|last1=Buterin|first1=Vitalik|last2=Hitzig|first2=Zoe|last3=Weyl|first3=Glen|date=2019|title=A Flexible Design for Funding Public Goods|url=https://pubsonline.informs.org/doi/abs/10.1287/mnsc.2019.3337|journal=Management Science|language=en|volume=65|issue=11|pages=5171–5187|doi=10.1287/mnsc.2019.3337|arxiv=1809.06421 |s2cid=198858039 }}</ref> and is now referred to as quadratic funding.

Quadratic funding has a close theoretical link with the VCG mechanism, and like VCG, it requires a subsidy in order to induce incentive compatibility and efficiency. Both mechanisms also fall prone to collusion between players and sybil attacks. However, in contrast to VCG, contributors only have to submit a single contribution – the total contribution to the public good is the sum of the square roots of individual contributions. It can be proved that there is always a deficit that the mechanism designer must pay.

One technique to reduce collusion is to identify groups of contributors that will likely coordinate and lower the subsidy going to their preferred causes.<ref>{{Cite journal|last1=Miller|first1=Joël|last2=Weyl|first2=Glen|last3=Erichsen|first3=Leon|date=2022|title=Beyond Collusion Resistance: Leveraging Social Information for Plural Funding and Voting|url=https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4311507|journal=SSRN|language=en|doi=10.2139/ssrn.4311507|ssrn=4311507 |s2cid=255261051 }}</ref>