Matching principle is one of the two most fundamental accrual principles, accrual principles having to do with timing, having to do with when revenue and expenses are recognized. The revenue recognition principle is the accrual principle governing revenue recognition. The matching principle, expense recognition principle, governs the time period that expenses should be recognized. Matching principle can seem more confusing than the revenue recognition principle because revenue recognition is the goal or objective of the business, expense generation not being the goal of the business. The reason for expenses are to help achieve the business goal, helping generate revenue. This is where we often refer to accrual expense recognition as the matching principle, the goal being to match expenses to the same time period they are used to achieve the goal of generating revenue. Expenses do not equal cash outflow but, according to the matching principle, represent assets used or liabilities incurred in order to generate revenue in the same time period.