Forex Trading is significantly driven by the comparison of economic strength of one country against the other. If USA's economic strength is better than that of lets say UK, then ofcourse, USD will be viewed as more stable and so GBP/USD currency pair will be in bearish direction.

So, next the legitimate question is how do the economists judge the economic strength?

Well, they used a basket of indicators to judge. The indicators are called as "Leading Economic Indicators"

Lets look at them briefly -

1. Initial Jobless Claims - By far one of the strongest indicators to judge how good is the economy. This indicator is used to influence the inflation and is also a component of Non Farm Payrolls.

2. Philadeplphia Fed Manufacturing Index - Frankly, I don't know its significance. If  you know, please share in the comments!!

3. New York Stock Exchange Index - Forex Market influences stoock market and Vice-versa. NYSE index is basically a way to tell what is the confidence level among investors to spend or invest money! A highly liquid market would mean that money is circulating. However a highly liquid market which is also controlled by bears would mean that investors are not confident of economy!

4. Commodities Market - Oil price naturally impacts the entire economy and is so powerful that it can drive the entiore election campaigns during election season! Alomg with it, price of gas and energy sectors is also considered.

5. Metal Prices and US Bonds - Gold, Silver, copper and platinum are the metals whose prices are considered to judge strength of economy. Also, US bonds prices are also monitored.

So, as you can see, it takes a lot of indicators to check how good is the economy and what factors should be changed like interest rates etc. to bring an ecomony on course which might be deviating.

So, it is all but natural that forex market is highly susceptible to such fundamental news releases.