Reproducibility

Reproducibility is one of the main principles of the scientific method, and refers to the ability of a test or experiment to be accurately reproduced, or replicated, by someone else working independently.

Reproducibility is different from repeatability, which measures the success rate in successive experiments, possibly conducted by the same experimenters. Reproducibility relates to the agreement of test results with different operators, test apparatus, and laboratory locations. It is often reported as a standard deviation.

While repeatability of scientific experiments is desirable, it is not considered necessary to establish the scientific validity of a theory. For example, the cloning of animals is difficult to repeat, but has been reproduced by various teams working independently, and is a well established research domain. One failed cloning does not mean that the theory is wrong or unscientific. Repeatability is often low in protosciences.

The results of an experiment performed by a particular researcher or group of researchers are generally evaluated by other independent researchers by reproducing the original experiment. They repeat the same experiment themselves, based on the original experimental description, and see if their experiment gives similar results to those reported by the original group. The result values are said to be commensurate if they are obtained (in distinct experimental trials) according to the same reproducible experimental description and procedure.

The basic idea can be seen in Aristotle's dictum that there is no scientific knowledge of the individual, where the word used for "individual" in Greek had the connotation of the "idiosyncratic", or wholly isolated occurrence. Thus all knowledge, all science, necessarily involves the formation of general concepts and the invocation of their corresponding symbols in language (cf. Turner).

Famous problems

In March 1989, University of Utah chemists Stanley Pons and Martin Fleischmann reported the production of excess heat that could only be explained by a nuclear process. The report was astounding given the simplicity of the equipment: it was essentially an electrolysis cell containing heavy water and a palladium cathode which rapidly absorbed the deuterium produced during electrolysis. The news media reported on the experiments widely, and it was a front-page item on many newspapers around the world. Over the next several months others tried to replicate the experiment, but were unsuccessful. At the end of May the US Energy Research Advisory Board found the evidence to be unconvincing, and cold fusion was dismissed as pseudoscience. Later on, successful replications by independent teams were reported in peer reviewed scientific journals, and, although the effect is not considered fully repeatable, the field eventually gained some scientific recognition. [See the [http://www.science.doe.gov/Sub/Newsroom/News_Releases/DOE-SC/2004/low_energy/index.htm U.S. DoE 2004 Cold Fusion Review] which states that half the reviewers found the evidences of excess heat convincing, and 1/3 found the evidences of nuclear reactions convincing. See the cold fusion article for more references.]

Nikola Tesla claimed as early as 1899 to have used a high frequency current to light gas-filled lamps from over convert|25|mi|km away without using wires. In 1904 he built Wardenclyffe Tower on Long Island to demonstrate means to send and receive power without connecting wires. The facility was never fully operational and was not completed, supposedly due to economic problems. Tesla's experiments have never been replicated.

ee also

* Accuracy
* Contingency
* Corroboration
* Falsifiability
* Hypothesis
* Inquiry
* Pathological science
* Precision
* Pseudoscience
* Scientific method
* Tautology
* Testability

References

* Turner, William (1903), "History of Philosophy", Ginn and Company, Boston, MA, [http://www2.nd.edu/Departments//Maritain/etext/hop.htm Etext] . See especially: [http://www2.nd.edu/Departments//Maritain/etext/hop11.htm "Aristotle"] .
* [http://www.iupac.org/goldbook/R05305.pdf Definition (PDF)]

Notes:

External links

* [http://physics.nist.gov/Pubs/guidelines/appd.1.html Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results; appendix D]
* [http://www.iupac.org/goldbook/R05305.pdf Definition of reproducibility in the IUPAC Gold Book]
* [http://arstechnica.com/journals/science.ars/2006/10/25/5744 Detailed article on Reproducibility]
* [http://www.jir.com/ "Journal of Irreproducible Results" (Spoof)]