It's difficult to say what effect one party having more support than polled has on another's chances because we have to worry about where the extra votes came from.

As an extreme example, since there are almost zero voters who are choosing between

SF and

FG, the two parties support levels might be completely independent of eachother. OTOH,

FG and the PDs were fishing in the same pool and losses for one were always gains for the other.

Even if we ignore the problem of dependence, given the theoretical accuracy of Irish polls it's very unlikely that any of the 3 parties would be 3% above its poll numbers, never mind all 3 of them.

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The margin of error Irish polls usually give you is

"If we've done everything correctly then there should be

a 95% chance of the actual number being within plus or minus 3% of what we say

in the worst case scenario of the electorate being evenly split on this question".

Voters are rarely evenly split on questions, so the 3% MoE is usually a bit conservative

(the further a party's support is from 50%, above or below, the more accurate its poll numbers should be).

If just over 1000 people were polled and exactly 20.0% said they were going to vote for party X then _in_theory_ there would be

a 25% chance of X's actual support being between 19.6% and 20.4%,

a 50% chance of X's actual support being between 19% and 21%,

a 75% chance of X's actual support being between 18.5% and 21.5%,

a 90% chance of X's actual support being between 18% and 22%,

a 95% chance of X's actual support being between 17.5% and 22.5%,

a 99% chance of X's actual support being between 17% and 23%,

a 99.5% chance of X's actual support being between 16.5% and 23.5%,

a 99.99% chance of X's actual support being between 15.25% and 24.75%,

a 99.999% chance of X's actual support being between 14.5% and 25.5%.

Of course, there also are a load of judgement calls pollsters have to make about stuff like how likely people are to vote, how likely they are to lie, how skewed the data collection process was, etc. that have an unknown effect on the numbers.

Irish people tend to get too hung up on plus or minus 3% - it's a good way of giving an idea of how accurate a poll is, but shouldn't be taken too literally.