Irish test voting system

PROPORTIONAL representation, the system in use for today's assembly elections in Northern Ireland, is a psephologist's delight and a valuable tool for voters who wish to express more than one preference.

The behind-the-scenes calculations to be made by electoral officers in totting up the votes are a mathematical nightmare, but for voters the process is straightforward.

In the single transferable vote version of PR, voters are presented with a list of say 20 candidates. They place the number 1 beside their first choice, the number 2 beside their second favourite and so on. They can stop at any point, or they can, if they wish, vote for every candidate. Most seem to vote for quite a few on the ticket. Northern Ireland has had 22 elections in the last 25 years, and fourteen of them have been held under PR.

Each of the 18 Westminster constituencies will return six assembly members, with between 15 and 22 candidates standing in most areas. When candidates reach a mathematically-calculated quota they are declared elected, the count then continuing until all six seats are filled.

The excess votes of successful candidates are re-distributed in line with the lower-preference votes on their ballot papers, while at other stages, candidates with too few votes are eliminated and their votes also re-distributed.

It is widely understood that lower preferences are often given not because of any tremendous enthusiasm but as the lesser of two evils. With a wide range of pro-assembly candidates in the field, voters are expected to transfer between them in large numbers.