Which impacts more on the workers of the project? - To reward the hard-working workers - To punished careless workers?

Nursing reward methodology is more effective to motivate the hard-working workers.
Before the punishment of careless workers, it is better to determine their genuine problems by psychological test method and try to solve their basic problems.
Try to determine their potential and groom them for utilizing in the favor of organization as assets.
If they are habitual then punish them