http://www.publications.parliament.uk/pa/cm200910/cmselect/cmsctech/memo/climatedata/uc3402.htm
“Computer code is also at the heart of a scientific issue. One of the key features of science is deniability: if you erect a theory and if anyone produces evidence that it is wrong then it falls. This is how science works: by openness, by publishing minute details of an experiment, some mathematical equations or a simulation; by doing this you embrace deniability.”

I’m not sure the use of the word deniability is correct in this context, what Popper was concerned about, indeed what caused him to originally deny the Theory of Evolution as a true theory is falsifiability. Later philosophers of science argued that falsifiability isn’t the true test of a theory and therefore science, but rather the process of deriving and testing predictions is a better description of how science really works.

Taking what another scientist has produced, and simply re-running the experiment is not how science is done, nor does it provide value in a scientific context. What does happen in science, as far as replicability is concerned, is not a replication of the experiment but a replication of the results. The same data may be used, but it is generally treated differently, with different methods, including code, in an attempt to falsify/verify a prediction based on the data.

It seems like IT people used to the rigid, narrow confines of programming languages and the zero error tolerances of hardware, where testing consists of examining and re-running the same code over and over, have a great deal of trouble understanding the habits of scientists with the releasing of data. Scientists expect other scientists to produce their own procedures and tests, and sometimes even collect their own data to test an hypothesis. Asking a scientist for not only the data but the code and the procedures is likely to just confuse or irritate him.