Reasons for raises

What's the determining factor in granting salary increases? A recent study shows that managers and workers disagree on the answers.
48% of managers believed "employees who do a better job get paid more", but only 31% of non-managers thought so;

46% of managers agreed "my last raise was based on performance", 71% of non-managers disagreed.

Source: 'Transforming pay plans", a Hudson survey of 10,000 employees, Mar. 20-26, 2006.