The debate rages about whether the Chancellor should implement a Plan B, or C or D or even Z. There seems to be a plethora of alternatives. But many of them share a key common theme. Namely, that an increase in public spending will boost output in the economy overall.
This was one of the revolutionary new ideas developed by Keynes, which he called the ‘multiplier’. An increase in public spending means that more people are employed, in the public sector itself of in building infrastructure. These in turn spend more money and the effect ripples across the economy. The final impact is a multiple – hence the word ‘multiplier’ – of the initial increase in spending.
http://www.tutor2u.net/blog/index.php/economics/comments/paul-ormerod-how-big-is-my-multiplier1
