Sensible economists accept that, because they’re determined by politicians, budgets are more about politics than economics. Pre-election budgets are more political than other budgets. And budgets coming before an election a government fears it may lose are wholly politically driven.

Welcome to this week’s budget. But here’s the point: whatever the motivation driving the decisions announced in the budget to increase this or reduce that, all the decisions have an effect on the economy nonetheless.

It’s a budget’s overall effect on the economy that macro-economists care about, not so much the politicians’ motives. So good economic analysis involves leaving the politics to one side while you focus on determining the economic consequences.

A glance at this week’s budget says that, with all its vote-buying giveaways, the budget will impart a huge further stimulus to an economy that was already growing strongly, with unusually low unemployment, but rising inflation.

What on earth are these guys up to, ramping an economy that doesn’t need ramping just to try to buy their re-election? But glances are often misleading, and the story’s more complicated than that.

You can’t judge the “stance” of fiscal (budgetary) policy adopted in a particular budget – whether it will work to expand aggregate (total) demand (spending) in the economy or to contract demand – just by looking at the few of its many “measures” (policy changes) that hit the headlines, while ignoring the other hundred measures it contained.

And, as with many concepts in economics, there are different ways you can measure them, with the different ways giving you somewhat different answers.

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