In his 2003 paper Escaping from a Liquidity Trap and Deflation: The Foolproof Way and Others Lars E.O. Svensson describes his Foolproof Way of escaping from a liquidity trap — experienced by countries such as Japan, and lately the US, when central bank interest rates are close to zero.
The Foolproof Way consequently consists of announcing and implementing three measures: 1) an upward-sloping price-level target path, starting above the current price level by a price gap to undo; 2) a depreciation and a crawling peg of the currency; and 3) an exit strategy in the form of the abandonment of the peg in favor of inflation or price-level targeting when the price-level target path has been reached.
As discussed in the previous subsection, a currency depreciation and a crawling peg is unique in providing the central bank with a concrete action that demonstrates the central bank’s commitment to a higher future price level, establishes credibility for the peg, induces private-sector expectations of a higher future price level, and stimulates the economy by reducing the real interest rate. As argued, via a depreciation and a crawling peg with a rate of appreciation approximately equal to the average foreign interest rate, the central bank can actually implement approximately the optimal way to escape from a liquidity trap and strike the optimal balance between current stimulus of the economy and the future price level. Furthermore, as discussed, the exchange rate is unique in providing a relatively direct measure of the private-sector expectations of the future price level.