reproduce

Reproducibility is the degree of agreement between measurements or observations conducted on replicate specimens in different locations by different people. Reproducibility is part of the precision of a test method.^[1]

Reproducibility also refers to the ability of an entire experiment or study to be reproduced, or by someone else working independently. It is one of the main principles of the scientific method. 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).

Reproducible data

Reproducibility is one component of the precision of a test method. The other component is repeatability which is the degree of agreement of tests or measurements on replicate specimens by the same observer in the same laboratory. Both repeatability and reproducibility are usually reported as a standard deviation. A reproducibility limit is the value below which the difference between two test results obtained under reproducibility conditions may be expected to occur with a probability of approximately 0.95 (95 %). ^[2]

Reproducibility is determined from controlled interlaboratory test programs.^[3][4]

Reproducible research

The term reproducible research was first proposed by Jon Claerbout at Stanford University and refers to the idea that the ultimate product of research is the paper along with the full computational environment used to produce the results in the paper such as the code, data, etc. necessary for reproduction of the results and building upon the research.^[5][6][7]

John P. A. Ioannidis wrote:

• While currently there is unilateral emphasis on "first" discoveries, there should be as much emphasis on replication of discoveries."^[8]

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.

Examples of irreproducible results

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 ("cold fusion"). 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 (see science by press conference). Over the next several months others tried to replicate the experiment, but were unsuccessful.

Nikola Tesla claimed as early as 1899 to have used a high frequency current to light gas-filled lamps from over 25 miles (40 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 due to economic problems.^[9]

See also

References

• Turner, William (1903), History of Philosophy, Ginn and Company, Boston, MA, Etext. See especially: "Aristotle".
• Definition (PDF), by International Union of Pure and Applied Chemistry

External links

Look up reproducibility in Wiktionary, the free dictionary.

• Reproducible Research in Computational Science
• Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results; appendix D
• Definition of reproducibility in the IUPAC Gold Book
• Detailed article on Reproducibility
• Reproducible Research Planet
• ReproducibleResearch.net