99 years ago today, 16 June 1922, the proportional representation single transferable vote system (PR–STV) was first used in Ireland in elections.

It is a system whereby Vote 1 goes to the first choice candidate, Vote 2 to the second and so on.  In Ireland, all elections – Dáil, Seanad, Presidential, European and local elections – are conducted using the system.

Under PR-STV, an elector's vote is initially allocated to his or her most-preferred candidate. After candidates have been either elected (winners) by reaching a quota or eliminated (losers), surplus votes are transferred from winners to remaining candidates (hopefuls) according to the surplus ballots' ordered preferences. The system minimizes "wasted" votes and allows for approximately proportional representation without the use of party lists.

The local elections of 1922 were contested on the same day as the Draft Irish Constitution, the 'Treaty' was published. It was, significantly, the first election to be conducted under the Proportional Representation System.

A contributor to the Cork Examiner newspaper penned the following verse, explain­ing the system, on the morning of the election:

How to Vote

Put Figure 1 to the name of your favourite

And 2 to the next you prefer

Then put 3, 4 and 5 in the way you think right

Against three of the other names there.

Another anonymous correspondent gave his views on the likely outcome of the contest:

The PR–STV system is also used in Malta, the Australian Senate, and some city elections worldwide.