The Coleman-Shapley-index: Being decisive within the coalition of the interested

André Casajus and Frank Huettner
Additional contact information
André Casajus: HHL Leipzig Graduate School of Management
Frank Huettner: ESMT Berlin

No ESMT-18-03, ESMT Research Working Papers from ESMT European School of Management and Technology

Abstract: The Coleman Power of the Collectivity to Act (CPCA) is a popular statistic that re flects the ability of a committee to pass a proposal. Applying the Shapley value to this measure, we derive a new power index that indicates each voter's contribution to the CPCA. This index is characterized by four axioms: anonymity, the null voter property, transfer property, and a property that stipulates that sum of the voters' power equals the CPCA. Similar to the Shapley-Shubik index (SSI) and the Penrose-Banzhaf index (PBI), our new index emerges as the expectation of being a pivotal voter. Here, the coalitional formation model underlying the CPCA and the PBI is combined with the ordering approach underlying the SSI. In contrast to the SSI, the voters are not ordered according to their agreement with a potential bill but according to their vested interest in it. Among the most interested voters, the power is then measured in a similar way as with the PBI. Although we advocate the CSI against the PBI to capture a voter's in fluence on whether a proposal passes, the CSI gives new meaning to the PBI. The CSI is the decomposer of the PBI, splitting it into a voter's power as such and a her impact on the power of the other voters by threatening to block any proposal. We apply the index to the EU Council and the UN Security Council.

Keywords: Decomposition; Shapley value; Shapley-Shubik index; power index; Coleman Power of the Collectivity to Act; Penrose-Banzhaf index; EU Council; UN Security Council (search for similar items in EconPapers)
JEL-codes: C71 D60 (search for similar items in EconPapers)
Pages: 22 pages
Date: 2018-05-08
New Economics Papers: this item is included in nep-cdm and nep-gth
References: Add references at CitEc
Citations: View citations in EconPapers (2) Track citations by RSS feed

Downloads: (external link)
http://static.esmt.org/publications/workingpapers/ESMT-18-03.pdf First version, 2018 (application/pdf)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:esm:wpaper:esmt-18-03

Access Statistics for this paper

More papers in ESMT Research Working Papers from ESMT European School of Management and Technology Contact information at EDIRC.
Bibliographic data for series maintained by ESMT Faculty Publications ().