ON Monday at lunchtime Labour's leader Ed Miliband was subjected to a fierce interview by Martha Kearney on the BBC Radio 4's World at One. The main subject of contention was Labour's economic policy, and in particular whether the party's plan for a temporary cut in Value Added Tax would increase government borrowing. Mr Miliband did not want to say this, only that, because it would stimulate growth, it would help bring down government debt in the medium term. This was not an assured performance by Mr Miliband, but beyond that it seemed to me, perhaps unfairly, that he only had a superficial grasp of the economics involved. If so, he shares this superficial understanding with many members of his party, who lap up quotes from economic commentators such as Paul Krugman, and marry it to half-digested economic theory. So how is it meant to work? How can a temporary tax cut reduce government debt?
Let's start with the Keynesian multiplier, which is widely taught in basic economics, and which I suspect comes to mind to most people here. You really have to do a bit of maths to understand the implications. Suppose you have an economy with a national income of £100bn a year, and an average tax take of 40%. You decide on a 1% stimulus with a temporary tax cut of £1bn. As people receive the extra money, 40% of it goes in tax, and they spend, say 80% of the rest on domestic goods and services (it doesn't work if people use it to pay off debt or spend it on a foreign made car...). This adds £480m to the economy with extra expenditure straightaway. And this process continues in a virtual but diminishing circle, as that £480m is taxed, spent and so on. If everything turns out to be mathematically consistent the stimulus adds over £900m to the economy. You have nearly 1% growth! This has cost the taxpayer (added to national debt) of £1bn in the first instance, but a lot of this has come back in extra taxes from the growth.
This is what people half remember when economic experts like Mr Krugman say that stimulus can reduce debt. But there are two problems. First of all, although on my fairly realistic assumptions most of the cost is clawed back, about a quarter of it isn't. Keynesian stimulus cannot pay for itself at this simple, basic level unless people increase their spending by more than the stimulus itself. And secondly, it is a one-time event, so that you get 1% growth for one year, and then it stops, unless you repeat the giveaway. This tax cut is temporary. When you put taxes back up again, the whole process goes into reverse and the economy shrinks back to where it started. Something very like this happened to the last Labour government's temporary cut in VAT: a small bounce that was undone when the cut had to be reversed, which, of course, they then blamed on the Coalition.
All this is well known to the Paul Krugmans of this world though, otherwise they wouldn't be writing economics textbooks and winning Nobel laureates. When they advocate stimulus they are actually talking about something else: the effect of such a stimulus on the national zeitgeist. That 1% lift may make people and businesses happier. Businesses go out and invest more money; people save less, perhaps thinking that their share and property values will go up, and consume more. If this happens then all bets are off; the economy grows further, the government gets more taxes and the stimulus can pay for itself quite quickly and easily. Investment is particularly important; Maynard Keynes's critical insight was that recessions happen when investments don't match the amounts people save.
What to say about this? There are two potential snags and an irony. The first snag is that the zeitgeist is a hard thing to manage. The whole thing can be undone by another crisis from the Eurozone, for example, which might reduce prospects for exports and dent confidence generally; or there could be some other crisis. The second snag is that this model of short-term growth assumes that there is spare capacity in the economy. When people and businesses go out and spend, domestic companies can readily ramp up production, employ new people and so forth. This is usually the case in a recession. But not always. In the 1970s, after the price of oil skyrocketed, the economy had to be restructured in order to grow - which was particularly hard because of the trade unions. Attempts to stimulate the economy simply led to high inflation while doing nothing for unemployment. Today, more flexible and globalised markets seem to have reduced the inflation threat - but stimulus can still be dissipated on imports and asset prices. What of the British economy now? Many commentators think that the British economy should be "rebalanced", reducing its dependence on financial services and North Sea oil, as well as excessive private consumption fuelled by debt and property prices.
These potential snags to stimulus are why many critics of the government, such as the FT's Martin Wolf, and many Liberal Democrats, such as the Social Liberal Forum, say that any stimulus should take the form of added public expenditure on investment, in infrastructure and homes. Since these have an inherent value, and help expand the economy's capacity, there should be much less risk. This is a sensible idea in theory that is a lot less easy in practice. The public sector has a tendency to invest in wasteful projects for political rather than economic reasons.
This is where Labour's plans are quite distinctive. They talk about temporary tax cuts, and hint at increased current expenditure. This is founded on a belief that there was not much of a problem with the pre-crisis economy, or unsustainable about the growth rates achieved in the years leading up to it. The crisis was simply a problem with the global financial system, and the country's poor performance since is down to incompetent economic management from the Coalition. This is pretty much what Tony Blair said in his recent piece for the New Statesman. If you believe this then capacity is not at issue, and the zietgeist should be readily easy to fix.
And the irony? Left wing economic commentators like to laugh at the "Voodoo economics" of Laffer curves and self-funding tax cuts advocated by far-right commentators. Paul Krugman talks about their belief in the "confidence fairy". But the left's economic beliefs are no less dependent on their own confidence fairy.