Separability problem
Encyclopedia
The separability problem is a concept from the field of social choice theory
that describes the situation where two or more issues up for vote on a ballot either are, or are perceived as, related.
The separability problem commonly manifests itself most intensely in referendum
s and in voting on multiple charges before juries
or panels of judge
s, where simultaneous voting is employed. Some or all voters view the approval or disapproval of one issue dependent on the approval or disapproval of another. The voters have no information on the outcome of related issues, so they simply cast their first preference votes. The outcomes of these decision-making polls are often displeasing to a majority of voters merely because simultaneous voting denied them the information on outcomes of individual issues or the opportunity to express preferences of outcomes of related issues.
The solution to the separability problem for referendums would be set-wise voting, where the voter can express preferences for outcomes of related issues, as this process needs to be done at a particular time. For matters before juries or judicial panels, either set-wise or sequential voting can be employed to mitigate this problem, as all votes need not be cast in one instance. If sequential voting were employed, the outcome of every vote tally on an issue would be announced before a vote on the next issue would be taken. The drawback to sequential voting in this case would be that there is no means to guarantee that a juror would actually change a successive vote based on a prior verdict.
Social choice theory
Social choice theory is a theoretical framework for measuring individual interests, values, or welfares as an aggregate towards collective decision. A non-theoretical example of a collective decision is passing a set of laws under a constitution. Social choice theory dates from Condorcet's...
that describes the situation where two or more issues up for vote on a ballot either are, or are perceived as, related.
The separability problem commonly manifests itself most intensely in referendum
Referendum
A referendum is a direct vote in which an entire electorate is asked to either accept or reject a particular proposal. This may result in the adoption of a new constitution, a constitutional amendment, a law, the recall of an elected official or simply a specific government policy. It is a form of...
s and in voting on multiple charges before juries
Jury
A jury is a sworn body of people convened to render an impartial verdict officially submitted to them by a court, or to set a penalty or judgment. Modern juries tend to be found in courts to ascertain the guilt, or lack thereof, in a crime. In Anglophone jurisdictions, the verdict may be guilty,...
or panels of judge
Judge
A judge is a person who presides over court proceedings, either alone or as part of a panel of judges. The powers, functions, method of appointment, discipline, and training of judges vary widely across different jurisdictions. The judge is supposed to conduct the trial impartially and in an open...
s, where simultaneous voting is employed. Some or all voters view the approval or disapproval of one issue dependent on the approval or disapproval of another. The voters have no information on the outcome of related issues, so they simply cast their first preference votes. The outcomes of these decision-making polls are often displeasing to a majority of voters merely because simultaneous voting denied them the information on outcomes of individual issues or the opportunity to express preferences of outcomes of related issues.
The solution to the separability problem for referendums would be set-wise voting, where the voter can express preferences for outcomes of related issues, as this process needs to be done at a particular time. For matters before juries or judicial panels, either set-wise or sequential voting can be employed to mitigate this problem, as all votes need not be cast in one instance. If sequential voting were employed, the outcome of every vote tally on an issue would be announced before a vote on the next issue would be taken. The drawback to sequential voting in this case would be that there is no means to guarantee that a juror would actually change a successive vote based on a prior verdict.
External links
- Voting on Referenda:The Separability Problem and Possible Solutions Article by Steven J. Brams, D. Marc Kilgour, and William Zwicker.
- A problem with referendums Article by Dean Lacy and Emerson Niou.
- The Paradox of Multiple Elections Article by Steven J. Brams, D. Marc Kilgour, and William Zwicker.
- The Probability of Inconsistencies in Complex Collective Decisions Article by Christian List.