The fact is the user data to which rule conditions are applied. At design time a fact is a reference to that data.

Facts have two categories – Short Term Facts and Long Term Facts. Consider a loaning process of any Bank. We can think a “loan application” as short term fact. Short team facts are business information which changes per occurrence. On the contrary, “interest rates” do not change very regularly. This business information is steady and we can consider it a long term fact.