In science, priority is the credit given to the individual or group of individuals who first made the discovery or propose the theory. Fame and honours usually go to the first person or group to publish a new finding, even if several researchers arrived at the same conclusion independently and at the same time. Thus between two or more independent discoverers, the first to publish is the legitimate winner. Hence, the tradition is often referred to as the priority rule, the procedure of which is nicely summed up in a phrase "publish or perish", because there are no second prizes. In a way, the race to be first inspires risk-taking that can lead to scientific breakthroughs which is beneficial to the society (such as discovery of malaria transmission, DNA, HIV, etc.). On the other hand, it can create unhealthy competition and incentives to publish low-quality findings (e.g., quantity over quality), which can lead to an unreliable published literature and harm scientific progress.

 

Note:   The above text is excerpted from the Wikipedia article Scientific priority, which has been released under the GNU Free Documentation License.