NI: making sense of the mathsAs the count is underway BBC Parliament considers the electoral system for the Northern Ireland Assembly.
The Good Friday Agreement of 1998 determined that elections to the 108 seat assembly should be by the Single Transferable Vote (STV) system.
This form of proportional representation (PR) was deemed most suitable for reflecting the voting preferences of diverse constituencies choosing from a variety of parties.
The STV system requires electors to vote for at least one candidate and then express preference for as many others as they wish.
Pick a number
The relative importance of the selections is reflected by a number written next to the candidate's name on the ballot paper - the first choice numbered '1' and so on.
Election depends on candidates receiving a
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The formula - or 'Droop quota' - used to work out who wins a seat is to divide the total number of valid voting papers cast by the number of seats to be filled plus one.
When the quota has been calculated the first preference votes are counted and anyone getting over the quota is elected.
Stage two: the surplus
In stage two, the surplus votes - the number of votes over the quota - of the leading candidate are transferred among the other candidates.
Each surplus vote is valued by dividing the surplus by the total number of votes received by the leading candidate.
The second preferences on the ballot papers of those electing the leading choice is then considered.
The number of votes for the second preference is multiplied by the value of the surplus and this figure is added to the number of first preference votes gained by the - in this case - second preference candidate.
If this second candidate then achieves over the quota, the person is elected.
Protracted process
If no-one is elected in stage two, the bottom candidate is eliminated and his votes are re-distributed according to the other preferences.
A large number of candidates and - or - an evenly spread pattern of voting can make the STV process very protracted.
For example the Stangford constituency went through 18 stages to elect six out of the total 22 candidates in the Northern Ireland Assembly elections of June 1998.
Executive choice
When the members of the assembly have been chosen there is then the even more troublesome question of selecting members of the executive.
The Good Friday Agreement stipulated ministerial portfolios should be allocated according to the d'Hondt system.
However Sinn Fein and the DUP have yet to settle on a satisfactory power-sharing agreement for the executive in Stormont.
If the DUP manage to control the majority of unionists they will demand a replacement of the Good Friday Agreement.
Barring recounts the final result is expected on Friday afternoon.
BBC Parliament will be broadcasting the Northern Ireland election's results programme from 1100 to 1300 GMT on Friday 28 November