Mr Barnett was not expected to lead the Liberals to the March election. Credit:Trevor Collens In an article in the latest Reserve Bank Bulletin, Thomas Carr, Kate Fernandes and Tom Rosewell argue that looking at what's been happening from state to state does much to help explain what the Australian Bureau of Statistics is telling us about developments in the national economy. It also helps explain why Colin Barnett was thrown out of office so unceremoniously in WA last Saturday. Forget the politicos' obsession with the role of One Nation, the deeper explanation is economic. After peaking at growth of 9.1 per cent in gross state product (the state equivalent of gross domestic product) in 2011-12 at the height of the mining boom, growth slumped to just 1.9 per cent in 2015-16. There's nothing new about governments getting tossed out when their boom turns to bust. Especially when it becomes apparent what a hash you made of the good times, spending like there was no tomorrow.

BHP hit a five-month high, closing up 2.3 per cent at $25.85. To see how the two-speed worm has turned, consider this. In 2015-16, real GDP grew by 2.8 per cent for the year as a whole. Within this, NSW's real GSP grew 3.5 per cent and Victoria's 3.3 per cent. By contrast, Queensland's grew 2 per cent and, as we've seen, WA's 1.9 per cent. (If you must know, South Australia's was 1.9 per cent and Tasmania's 1.3 per cent.) What's that? You think WA's annual growth of 1.9 per cent doesn't sound all that terrible? It's being held up by the increased volume of WA's exports of iron ore and liquefied natural gas. Trouble is, that generates next to no additional jobs. In mining, most of the jobs come from building new mines. When construction ends, the building workers go back where they came from (which ain't Perth).

Our trio from the RBA say that, over the period of the resources boom's build-up and let-down, differences between the performance of the states have been explained mainly by differences in private investment spending. Consumer spending accounts for a far bigger slice of GDP/GSP than investment spending. And consumer spending has been much less variable between the states than investment spending – although it's been weakest in WA. Consumers keep their spending reasonably smooth from year to year. They do this by cutting back their rate of saving when their incomes aren't growing fast enough. We know from the national accounts that, while wages and employment growth have been weak in recent times, households have been progressively lowering their rate of saving to help keep their consumption steady. That's normal cyclical behaviour. What we now know from the RBA trio's investigations, however, is that pretty much all the decline in the national saving ratio is explained by the actions of West Australians and Queenslanders. Ah.

Another national-level story we're familiar with says the economy is making a transition from mining-led to non-mining-led growth. So, as mining projects are completed and mining investment spending falls way back, we need strong growth in non-mining business investment to take its place. The national accounts tell us it's not been happening. You've heard all the wailing and gnashing of teeth – not to mention speculation about causes – that's accompanied this bad news. But here again the RBA trio's data diving shows the story in a different light. While mining investment was booming in the mining states, so was non-mining investment in those states. Confidence in one part of the local economy spills over to other parts. While this was happening in the mining states, non-mining business investment in the other states was weak. Illustration: Glen Le Lievre

As the trio almost admit, this was part of the RBA's dastardly plan to ensure the mining boom didn't cause runaway inflation – as every previous commodity boom had. While the politicians were letting foreign miners make all the crazy investments we now realise they did – leaving us with a gas-bonanza-caused energy crisis – the RBA had to "make room" for the miners by holding back the rest of the economy and, in particular, non-mining business investment. It would have been willing to achieve this restraint by holding interest rates higher than otherwise needed but, fortunately for it, most of the work was done by the abnormally high exchange rate, which crunched manufacturers, tourism and foreign student education. Back to the now. While the national figures reveal non-mining investment failing to show signs of recovery, the trio's data diving shows it's actually falling in the mining states (as lack of confidence in mining spills over) but recovering elsewhere. In NSW, non-mining investment has grown at an average rate of 8 per cent a year for the past three years. In Victoria, it's been 4 per cent.