The publication of an article or a working paper is only part of the scientific process. Scrutiny by the scientific community during the peer-review process and later through replication attempts and extensions of the original work should be part of it. Unfortunately, very little of that is happening in economics. Indeed, a significant hurdle is that very often the computer code and/or the data used for the analysis are not disseminated. While some journals now make this a requirement for publication, there is otherwise very little incentive for researchers to make this available. In part, this is also a question of culture, as we are not used to cite datasets, for example, and prefer to acknowledge their use in a footnote.
To change this culture and push for making code and data more readily available, the Open Knowledge Foundation and put together a set of Principles on Open Economics. Read them and sign on if you think you are willing to endorse them.
On the RePEc front, we are working to get datasets indexed as well. If interested in participating in this, contact me.