Ed Felten has an interesting post on Secrecy in Science:
This describes an interesting dynamic that seems to occur in all scientific fields — I have seen it plenty of times in computer science — where researchers withhold results from their colleagues for a while, to ensure that they get a headstart on the followup research. That’s basically what happens when an astronomer delays announcing the discovery of an object, in order to do followup analyses of the object for publication.
The argument against this secrecy is pretty simple: announcing the first result would let more people do followup work, making the followup work both quicker and more complete on average. Scientific discovery would benefit.
The argument for this kind of secrecy is more subtle. The amount of credit one gets for a scientific result doesn’t always correlate with the difficulty of getting the result. If a result is difficult to get but doesn’t create much credit to the discoverer, then there is an insufficient incentive to look for that result. The incentive is boosted if the discoverer gets an advantage in doing followup work, for example by keeping the original result secret for a while. So secrecy may increase the incentive to do certain kinds of research.