evidence: Even using the modified measure of national income (GNI ), the differential remains significant. Expressed per head, GNI is more than 10% higher than GDP per head in the UK and roughly 45% higher than GDP per head in NI. [...] Looking again at the public sector, is government spending in this area indeed a key differential? Certainly the public sector is a bigger proportion of the economy in NI than in the Republic. Some 24% of Irish employment is in public administration, health and education and in NI the figure is almost 30%. A differential, but perhaps less pronounced than many expect. Spending comparisons are rather tricky due to a range of definitional issues. For example, Ireland incurs spending on national debt and central services (like the Treasury) which NI does not. But taking a subset of public services, namely education, health, justice, social protection (including benefits and pensions) agriculture and transport; spending is actually very similar on a per head basis at current exchange rates.