On Elections

How people elect parliaments

Northern Ireland


Specific elections: 1998 – 2003 – 2007 – 2011 – 2016 – 2017


Parliamentary institutions in Northern Ireland have to date been created, modified and dissolved through legislation of the Parliament of the United Kingdom.

Arising out of Irish independence and partition in the early 1920s, Northern Ireland had a separate bicameral Parliament from 1921 until 1972, when it was dissolved during the civil unrest in the region. Throughout these 51 years the Ulster Unionist Party held a governing majority of seats in the Parliament. At its first two elections, the 52-seat House of Commons of this Parliament was elected by the single transferable vote (STV) voting method, but from 1929 the dominant party legislated to change the electoral method to single-member divisions with plurality voting (first-past-the-post), which method then continued until 1972.

Following the Good Friday Agreement in 1998, a new unicameral Assembly (Tionól Thuaisceart Éireann (Irish), Norlin Airlan Assemblie (Ulster Scots)) was created.

The sole chamber of the Assembly now consists of 90 members. The members are directly elected in 18 electoral divisions each electing 5 members by the STV method.  From 1999 to 2017 the Assembly had 108 members, with 6 members elected in each of the 18 divisions. The boundaries of the 18 electoral divisions have for convenience been identical to the boundaries of the region’s constituencies for electing members to the national UK House of Commons.

Terms are up to five years.

Within the scope of the powers devolved to it by the Parliament of the United Kingdom, Northern Ireland has the representative parliamentary system of government, in which nominal executive authority is vested in the Queen of the United Kingdom. However, actual executive power for Northern Ireland is exercised by the First Minister on the basis of the continuing confidence of a majority in the Assembly. The legislation creating the Assembly and the devolved government specifies the areas of executive responsibility of the Northern Ireland administration, as opposed to powers retained by the national government.

The appointment of the Northern Ireland Executive follows two unique practices, designed to bring about ‘consociational’ government uniting the unionist and nationalist communities into a cooperative form of government.

Firstly, a Northern Ireland government may only be formed if the largest Assembly party representing nationalists and the largest party representing unionists agree on jointly electing the First Minister and the Deputy First Minister, nominated by their respective parties (the First Minister coming from the community with the largest vote share, which to date has always been the unionist community.) If either of these executive officers resigns the other also automatically leaves office, and if one party refuses to nominate a replacement, the government cannot retain office. In early 2017 such a situation occurred, resulting in early elections.

Secondly, seats in the governing ministry are allocated proportionally among any political parties in the Assembly who agree to join in the governing coalition, in proportion to their numbers of Assembly seats as calculated by the D’Hondt method.

Commentary and analysis




[Inequality in the effective influence of voters caused by variations in division enrolments]

[nomination openness – party configurations]

[summary of results]

[Inequality in the effective influence of voters caused by variations in division turnouts (formal votes)]

[inequality by margins]

Specific elections

1998 – 2003 – 2007 – 2011 – 2016 – 2017




[data source – data completeness – anomalous contests]


[Datasets are not yet published]

  • OnElections election results – UK-NI-1998-2017 v1.xls
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