How people elect parliaments
OnElections election data UK-HC-2017 v1.xls
The election was for 650seats.
The composition of the assembly was subdivided into 00 electoral regions based on regions. These were allocated numbers of seats in proportion to their total population of inhabitants. The allocation was most recently reviewed in 2000. [any divergence from proportionality]
The leading parties contesting this election included the following:
[comments on openness of, barriers to and stability of party formation and change]
A total of 000.0 million persons were estimated to make up the eligible electorate. 000.0 million persons were registered to vote. 000.0 million voters actually cast a valid vote. On these results the overall turnout of voters casting a valid vote was 00.0% of eligible voters and 00.0% of registered voters.
The electoral system allowed voters to vote directly for individual candidates.
The electoral system was structured around a system of single-member electoral divisions, such that only candidates who were registered as resident in the same defined local electoral division as the voter were available to be selected as representatives. Moreover for each political party only one candidate was nominated, greatly limiting voter choice.
Because the system allowed only a single chosen candidate to be supported, many voters would have felt pressure to cast their vote for candidates other than their genuine first preference based on their anticipation of which candidates had the most viable prospect of becoming the plurality winner, or else out of a desire to prevent a specifically opposed leading candidate from winning (tactical voting).
As a consequence of constraining the selection of representatives to a single elected member per electoral division, the electoral system introduced a large degree of variety in the effective influence of each vote.
Variation in the number of persons registered to vote in each of the 00 electoral divisions was 00.0% (as a co-efficient of variation between the division values). This is relatively high/low compared to similar international systems.
In addition, demographic concentrations of party electoral support across the electoral divisions made many contests politically ‘safe’, with only a relatively small number of divisions being highly contestable, greatly diversifying the variation in the vote margins of victory achieved by the elected MPs. For this election that outcome was 00.0% (as a co-efficient of variation between the division values), which is a high/low result compared to similar electoral systems.
The system for determining electoral division boundaries was governed by a constitution rule requiring xxx. Current legislation had established an independent/partisan process for determining boundaries. Boundaries were last revised in the year xxx. In this election the partisan boundary-setting constituted a deliberate gerrymander which is estimated to have resulted in an additional 00 seats won by the xxx party at the expense of the xxx party.
After this election an estimated 00.0% of the registered electorate had at least some representation in the xxx by one or more MPs of a party they supported. The actual proportion of the electorate who specifically voted for the sitting MPs was however a lower figure of 00.0%.
As noted above the members of the chamber were directly elected, and the degree of equality of influence of voters in their election was low.