The scientists at the Climate Research Unit (CRU) at the University of East Anglia have been slammed for not making their raw data, intermediate data and source code available.
Climate Research Unit at UEA
I think the problem has been that in many areas of science keeping data to yourself is commonplace and that this is seen as a reasonable way of working. It forces your competitors to obtain data from the original primary sources and for them to carry out every step independently of the work that you have done. This process makes the sum of knowledge built up by science more robust than if any of the original prepared data or source code, or data from intermediate steps is made available.
There are consequences to being more open. For instance if a competing researcher chooses to use your source code rather than writing their own they are likely to miss bugs in the code which means they will be repeating the same mistakes as you, or if a competing researcher uses prepared data you have made available rather than going back to the original primary sources then all that happens is that those mistakes get repeated. Using your competitors source code is not dissimilar to the idea of them borrowing your lab equipment to repeat your experiments. Anything less than working independently to your competitors on the same data or using your own experimental apparatus is repetition and not replication*.
It might be a pain, it might be more work, but the process of replicating other scientists work by doing as many steps as possible yourself is what makes the results of doing science robust. It is not necessary for good science to happen for people to have access to your original data when they can get it elsewhere. Making the data of the results of intermediate steps, your e-mails and your source code available is unnecessary for good science to happen, and has the potential for reducing the robustness of the scientific results.
It might not be appropriate in the case of Climate Science to keep to this process as there are too many interested parties outside of climate science. But this means we should think about the consequences of greater openness and the potential that this has for a reduction in the quality of science.
The requests for data from the Climate Research Unit has not been handled well, but I think the reason this is the case is not because of a conspiracy of silence but instead is due to the feeling by the researchers at CRU that this approach to doing climate science is inappropriate and at odds with their understanding of the scientific process.
If I had the approach to doing science challenged in the way that the researchers at CRU have been then I am not sure how I would have responded.
*Repetition: Repeating what some one else is done, perhaps using their source code, experimental apparatus or data they have prepared for processing. The robustness of the results is not improved by repetition.
*Replication: All the work is done independently by competing researchers at every step of the way. If the same or very similar results are achieved by more than one set of researchers then the results have been demonstrated to be robust.