Business Rules derive inferences and arrive at conclusions by reasoning about facts or premises using either deduction or induction.
An if-then statement in a declarative rule-based programming language is a business rule. Business rules are designed to solve complex problems that require reasoning (thinking) and knowledge in order to make intelligent decisions. Business rules can explain their reasoning process in order to justify their conclusions, decisions, and recommendations. Business rules are commonly used to create Intelligent Systems that reason and apply knowledge.
An if-then statement in a procedural programming language is not a business rule. It is simply a type of conditional statement designed to either control program branching or to conditionally execute sections of program code. If-then statements are commonly used in conventional programs that process data and manage information.
Reprinted from the Business Rules Knowledgebase