Feedback occurs when a change influences something that, in turn, affects the starting variable. In a reinforcing loop, the effect returning around the loop supports the original change.

For example, interest added to a savings balance can increase the amount on which later interest is calculated. With a fixed positive rate, no deposits or withdrawals and no fees, that particular model gives compound growth.

Loop type alone does not tell you an exact growth rate or future outcome. Other influences, limits and changing relationships still matter.