Ireland STV not much in need of reform, says the Oxford Handbook of Electoral Systems

Oxford Handbook of Electoral Systems (2018) had many positive things to say about Ireland and its use of STV.

says its use of relatively-low District Magnitude districts means some dis-proportionality t least bin relation to first preference votes but points out rightly that "any measure of dis-proportionality that relies just on the party share of first preference votes can be unfair to the principle of the system, which is to pick the winner(s) that a majority would favour in a run-off. Lower preference matter, and they are supposed to." (p. 658)

points out that quota in a three-seat district is 25 percent; four-seat 20 percent, 16.7% in a five-seat district.

but says that history says that there is a 50/50 chance for election of a candidate with 17% in a three-seat district, 13% in a four-seat district, 11% in a five-seat district. (p. 657)

in about 2010 about 80 percent of votes moved to another candidate of the same party but by 2018 that proportion of "intraparty solidarity" has decreased to 60 percent.

Sinn Fein though showed in 2016 tht 2/3rds of its voters gave both of their top preferences to SF. (p. 659)

meantime intraparty conflicts is intense in some districts in some elections.

incumbents have more often lost to someone of the same party that to someone of another party (p. 662)

Average vote spread preference over there parties, and a significant minority spread preferences over four parties.  (p. 660)

also fewer votes going to just the two largest parties.

once 90 percent went to top three (FG, FF, Labour) with 85% going to the two largest (FF and FG) but in 2016 the three top parties got just 64 % of the vote.

2016 the three old parties (FG, FF, Labour) won just 56% of the vote among them.

(Sinn Fein overtook Labour in 2016) (p. 655)

in 2018 it was noticed that more voters were rejecting all parties and voting for independent candidates. (p. 663)

how many preferences are marked

100% percent mark first preference

94% preference mark 1 and 2,

74% mark 1, 2, 3.

40% mark 1, 2, 3, and 4. (p. 660)

Irish STV known for having members who devote lots of time to local concerns instead of national needs.

but Dail members likely do not engage in "clientelism" as "they cannot and do not provide material advantages to constituents" (p. 665) (whether that includes placement of government infrastructure or amenities in the district versus another district is not clear to me)

They do constituency work helping constituents get the services they are due.. they act as brokers interceding between the state agencies and citizens.

which in other societies is done by citizens' advice bureaus.

it is said Dail members spend 60/40 on national/local issues.

constituents say they would actually would like to see the balance 50/50. (p. 666)

The way STV works --

a party  needs a number of votes equivalent to 62% of quota to be 50/50 likely to win a seat if it runs just one candidate,

But a party needs a number of votes equivalent to 82% of quota to be as 50/50 certain to win a seat if it runs two candidates. (p. 664)

A second candidate can bring in more first-preference votes, but unless its gain is enough to overcome "the potential loss due to lower first-preference vote tallies for either candidate" and the "subsequent disadvantage in the count", it is not worth it.

"Over-nomination risks losing seats that could have been won." [but unstated is that the penalties for over-nomination are likely less than under FPTP or SNTV.] (p. 664)

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