“As a result” is an expression often used as a conjunctive adverbial phrase which implies a causal relationship —a relationship of cause and effect— between two clauses. The expression is a synonym of “therefore”, “consequently”, “as a consequence” “accordingly”, and “hence”. In order to be properly used, it should be preceded by a semicolon, like this:
Canals and railroads lessened the cost of moving goods; as a result, prices fell on goods from across the country due to lower shipping costs.
