English: Illustration of the effects of the majority criterion on different voting systems.

The left-to-right axis represents any spectrum of opinion, such as a typical political spectrum, desire for a particular pizza topping, etc.

The voters are distributed along that spectrum according to the bell curve at the top.

The voters vote honestly in the 5 different voting systems shown, choosing the candidate(s) closest to them on the ideological spectrum. So someone a little to the right of the Green candidate, under different systems, would vote like this:

• Plurality: Green
• Approval: Green and Yellow ("Voters are assumed to vote for all candidates within an acceptable distance.")
• Borda/Condorcet/IRV: Green > Yellow > Red

The votes are then tallied according to the different systems and the winner is shown in the bars on the bottom, if the population were centered on that point.

When the population is as shown, the majority prefers the Red candidate over the others. Systems that follow the Majority Criterion (plurality, Condorcet, and IRV) choose the red candidate as the winner. Borda count is the only non-majority system, as it chooses the Yellow candidate. Approval voting is ambiguous regarding the majority criterion.

The tool also allows for bimodal distribution and uniform distribution. Both help the Yellow candidate even further under Borda count. "The Borda count is often described as a consensus-based voting system rather than a majoritarian one." Bimodal eliminate the Yellow candidate under Plurality and IRV, and uniform distribution eliminates Yellow under Plurality ("center squeeze effect").

Generated from http://zesty.ca/voting/voteline/, which is GPL software http://zesty.ca/code/

Similar to: https://electology.org/center-squeeze-effect