Tax individualisation worked, declares a new paper from the Economic and Social Research Institute. Well, it worked if the aim of policy should be to increase the number of women in the workplace as distinct from giving parents a real choice between home and work.

Tax individualisation was introduced to huge controversy in Budget 2000. It treats a married couple, where both are in paid employment, as essentially separate individuals and taxes them much more favourably than a married couple where one spouse stays at home to raise children or other dependents.

The end result is that a double-income married couple can end up paying almost €6,000 less in tax per annum than the couple next door on the same income where only one works. On top of that, the State is ploughing more and more money into making institutional child-care more affordable, meaning the two-income couple win on the double.

According to the ERSI paper by Dr Karina Doorley called ‘Taxation, work and gender equality in Ireland’, tax individualisation has increased female participation in the workplace by 5pc.

Is this a good thing? It is if your main aim is to swell the State’s tax revenues, and it is if your aim is to increase economic equality between men and women. But if it does not cohere with what married couples really want, and if it seems inherently unfair to impose a much bigger tax burden on single-income married couples than on double-income married couples, that is a different thing entirely.

It so happens that most people believe the State should equally support parents whether their choice is to both be in paid employment or for one to stay at home, at least during the early lives of their children. See here, here and here.

Given that people believe the State should be fairer to both sets of parents, tax individualisation remains as indefensible as it was back in 2000.

(For a more sustained argument against tax individualisation read here and here).