The factors mentioned above can also cause a currency to decline. For example, the currency of a country with low inflation will generally rise because that country's purchasing power is higher relative to other currencies. Even natural disasters such as earthquakes or tsunamis, which put a strain on a nation’s economy, can have a negative impact on a currency.
Fair Value strategy made use of in various financial markets. In the forex market, the fair value of a currency is determined based on the economic situation in a country. In order to use this forex strategy, traders must have an understanding about a few basic related to the economy, especially the GDP growth of the two economies whose currencies they plan to buy and sell. Other aspects to be considered include the unemployment rate and the inflation data.
If traders are positive on the prospects for the Yen, they would expect the number on the right to go down – i.e. the Yen would be getting stronger against the Dollar. Traders would be buying less Yen with a Dollar as the Yen got stronger. Similarly, if the Yen was expected to weaken, forex traders would expect the Yen number to go up, reflecting the fact that the dollar could buy more yen.