Election posters from 2007 Dublin South East Constituency from Wikipedia (open source).
Ireland between 2002-2007 seem to have had more independent TDs than there are parliamentary indepedents in west European parliaments (Most other European voting systems have either thresholds or party based list systems which either keep out or discourages independents).
One independent TD was elected in 2002 with less than 0.2% of the national share of first preference votes. That is with around 0.2% of the first preference vote they secured 0.6 of the seats…one Dáil seat equals about 0.6% of all 166 seats.
For much of the electoral history of the state, Fine Gael and Fianna Fáil have taken about 80% of the first preference vote; in recent elections this has dropped below 70%.
However, since 1987 no government has been able to form a single party majority. Coalition governments have actually been in power in Ireland 52% of the time over the period 1948-2002. Minority governments have featured 34% of the time between 1948-2002.
Although the Irish PRSTV system has been historically fairly proportionate (1 % of vote = 1% of seat), the bigger parties have been actually getting more seats than they deserve as measured by vote share. In election 2002 FF got 49% of the Dáil seats with 41% of the vote. The explanation appears to be transfers. More voters may be backing a coalition ‘pair’ or a preferred option of parties, although generally the evidence for coalition voting is limited enough.
Over time, just over half of FF TDs and over one third of FG TDs who lose their seat, lose it to another candidate of the SAME party!
Between 20-25% of Dáil deputies have had a close relative elected previously-these are ‘family TDs’. Notice also at cabinet level-several senior ministers were all ‘family TDs’ who partly inherited seats.
The turnover of TDs is relatively low-between 1927-2002 if we exclude retiring TDs, about 82% of TDs got re-elected. The figure is 75% get returned if we include retired TDs. In Denmark with a list system the re-election rate has been about 80% over the last 25 years. In New Zealand, where they switched to a mixed system (part list, part single TD constituencies) they have seen an increase in turnover-especially for list MPs. The constituency MPs are more likely to be relected.
The proportion of women elected to the Dail is low-usually in the teens. It was 13% in 2002. In Denmark where they use a list system (which is easy to vote, but hard to explain how it actually works), the number of female candidates was 29% in 2001, and the final number of female deputies was 38% This may well be because of deeper underlying social attitudes as much as the electoral system. In New Zealand their mixed system has seen an increase of women in Parliament-up from about 14% in 1987 to over 28% in 2002. However, once again we cannot infer simply that this electoral system change has on its own caused this. In fact a major part of the story is that internally several parties had adopted preferential rules to select more female candidates. Yet such policies probably go hand in hand with a list system-parties find it easier to place women in higher positions on the list meaning they are more likely to be elected.
Where did I get this information? See: Gallagher, Michael (2005) ‘The Discreet Charm of PR-STV’, pp.511-533 in Gallagher. M. and P. Mitchell (eds.) The Politics of Electoral Systems. Oxford: OUP