None of the models developed so far succeed to explain FX rates levels and volatility in the longer time frames. For shorter time frames (less than a few days) algorithm can be devised to predict prices. Large and small institutions and professional individual traders have made consistent profits from it. It is understood from above models that many macroeconomic factors affect the exchange rates and in the end currency prices are a result of dual forces of demand and supply. The world's currency markets can be viewed as a huge melting pot: in a large and ever-changing mix of current events, supply and demand factors are constantly shifting, and the price of one currency in relation to another shifts accordingly. No other market encompasses (and distills) as much of what is going on in the world at any given time as foreign exchange.
Supply and demand for any given currency, and thus its value, are not influenced by any single element, but rather by several. These elements generally fall into three categories: economic factors, political conditions and market psychology.