The document discusses the concept of a "balanced budget fiscal expansion" which aims to stimulate economic growth while maintaining a balanced budget. It involves cutting some spending, like public employee wages, and using the savings to increase other spending, like on infrastructure, that is expected to have a higher fiscal multiplier effect. Several factors can affect the size of the fiscal multiplier, including the type of spending/tax change, who benefits, private sector expectations and credit availability, and responses from monetary policy and other countries. Examples given of policies using this concept include bringing forward tax increases to fund temporary infrastructure spending or cutting some spending to increase capital investment.