Non-agricultural data can greatly affect the dollar value of the money market. A vibrant employment report can push up interest rates and make the dollar more attractive to foreign investors. They can earn interest income by holding US Treasury bonds. On the other hand, a bad employment report will weaken the demand for dollars, because it will bring trouble to the US stock market and put downward pressure on interest rates. Both of them will make the dollar less attractive to foreigners.
Under normal circumstances, the increase in non-agricultural data indicates that the US economy is improving, which is good for the US dollar and bad for gold and silver; On the other hand, if its value is reduced, it shows that the US economy is in a downturn, which is naturally bad for the US dollar and good for gold and silver.