People get paid for the hours they work. Contract role or permanent, it's still the same. Turn up, and get paid. You get more of what you reward. The feedback in this system is to make contractors work longer hours and permanent staff to leave as soon as their hours are up.
What if you rewarded achievements instead. Then all your employees would be focusing on how to improve processes and become more productive so they can get more rewards.
If you rewarded people on their individual achievements then this reinforces individualism. It would be better to reward teams as a whole. This would cause the team to focus on working together to achieve the goal in the most efficient way.
Imagine if your team signed up for chunks of work. Each chunk of work was worth a certain value to the business and so had an associated reward attached. The more the team gets done, the more the team gets paid. How do individuals get rewarded? The team should split the funds depending on how they feel each individual contributed to their success. Usually they would
split the money evenly. Occasionally they would reward individuals for outstanding work.
The hours you work is one of the resources you use to achieving your work. In what other situation do you pay someone for the amount of resources they use, rather than paying them for the outcome? Imagine I was a fork lift driver and I was paid for the amount of fuel I burned each day. Would this make me work harder? Would it make me get my work done faster? Would it make me put my fork lift up on bricks with the engine running?