Reproducibility
Encyclopedia
Reproducibility is the ability of an experiment
Experiment
An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...

 or study to be accurately reproduced, or replicated, by someone else working independently. It is one of the main principles of the scientific method
Scientific method
Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of...

.

The results of an experiment performed by a particular research
Research
Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...

er or group of researchers are generally evaluated by other independent researchers who repeat the same experiment themselves, based on the original experimental description (see independent review
Independent review
Independent review is the practice of having an expert, but independent evaluation of a set of results or artifacts produced by an author or organization. The practice appears in a large number of fields, including science, engineering, public policy, finance, medical practice, etc. In science, the...

).
Then they 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
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...

'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 research

The term reproducible research was first proposed by Jon Claerbout at Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...

 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.

John P. A. Ioannidis
John P. A. Ioannidis
John P. A. Ioannidis is a professor and chairman at the Department of Hygiene and Epidemiology, University of Ioannina School of Medicine as well as tenured adjunct professor at Tufts University School of Medicine and Professor of Medicine and Director of the Stanford Prevention Research Center at...

 wrote:
  • While currently there is unilateral emphasis on "first" discoveries, there should be as much emphasis on replication of discoveries."

Repeatability

Reproducibility is different from repeatability
Repeatability
Repeatability or test-retest reliability is the variation in measurements if they would have been taken by a single person or instrument on the same item and under the same conditions. A less-than-perfect test-retest reliability causes test-retest variability. Such variability can be caused by, for...

, 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
Standard deviation
Standard deviation is a widely used measure of variability or diversity used in statistics and probability theory. It shows how much variation or "dispersion" there is from the average...

.

While repeatability of scientific experiments is desirable, it is not considered necessary to establish the scientific validity of a theory. For example, the cloning
Cloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...

 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 protoscience
Protoscience
In the philosophy of science, a protoscience is an area of scientific endeavor that is in the process of becoming established. Protoscience is distinguished from pseudoscience by its standard practices of good science, such as a willingness to be disproven by new evidence, or to be replaced by a...

s.

Irreproducible results

In March 1989, University of Utah
University of Utah
The University of Utah, also known as the U or the U of U, is a public, coeducational research university in Salt Lake City, Utah, United States. The university was established in 1850 as the University of Deseret by the General Assembly of the provisional State of Deseret, making it Utah's oldest...

 chemists Stanley Pons and Martin Fleischmann reported the production of excess heat that could only be explained by a nuclear process ("cold fusion
Cold fusion
Cold fusion, also called low-energy nuclear reaction , refers to the hypothesis that nuclear fusion might explain the results of a group of experiments conducted at ordinary temperatures . Both the experimental results and the hypothesis are disputed...

"). The report was astounding given the simplicity of the equipment: it was essentially an electrolysis
Electrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...

 cell containing heavy water
Heavy water
Heavy water is water highly enriched in the hydrogen isotope deuterium; e.g., heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction...

 and a palladium
Palladium
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...

 cathode
Cathode
A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...

 which rapidly absorbed the deuterium
Deuterium
Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...

 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
Science by press conference
The term science by press conference is a phrase referring to scientists who put an unusual focus on publicizing results of research in the media. The term is usually used disparagingly...

). Over the next several months others tried to replicate the experiment, but were unsuccessful.

Nikola Tesla
Nikola Tesla
Nikola Tesla was a Serbian-American inventor, mechanical engineer, and electrical engineer...

 claimed as early as 1899 to have used a high frequency current to light gas-filled lamps from over 25 miles (40.2 km) away without using wires
Wireless energy transfer
Wireless energy transfer or wireless power is the transmission of electrical energy from a power source to an electrical load without artificial interconnecting conductors. Wireless transmission is useful in cases where interconnecting wires are inconvenient, hazardous, or impossible...

. In 1904 he built Wardenclyffe Tower
Wardenclyffe Tower
Wardenclyffe Tower also known as the Tesla Tower, was an early wireless telecommunications tower designed by Nikola Tesla and intended for commercial trans-Atlantic wireless telephony, broadcasting, and to demonstrate the transmission of power without interconnecting wires...

 on Long Island
Shoreham, New York
Shoreham is an incorporated village in Suffolk County, New York, United States. The population was 417 at the 2000 census.The Incorporated Village of Shoreham is inside the Town of Brookhaven.-Geography:Shoreham is located at ....

 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.

See also

  • Accuracy
  • Contingency
  • Corroboration
  • Falsifiability
    Falsifiability
    Falsifiability or refutability of an assertion, hypothesis or theory is the logical possibility that it can be contradicted by an observation or the outcome of a physical experiment...

  • Hypothesis
    Hypothesis
    A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...

  • Inquiry
    Inquiry
    An inquiry is any process that has the aim of augmenting knowledge, resolving doubt, or solving a problem. A theory of inquiry is an account of the various types of inquiry and a treatment of the ways that each type of inquiry achieves its aim.-Deduction:...


  • Pathological science
    Pathological science
    Pathological science is the process in science in which "people are tricked into false results ... by subjective effects, wishful thinking or threshold interactions". The term was first used by Irving Langmuir, Nobel Prize-winning chemist, during a 1953 colloquium at the Knolls Research Laboratory...

  • Accuracy and precision
    Accuracy and precision
    In the fields of science, engineering, industry and statistics, the accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual value. The precision of a measurement system, also called reproducibility or repeatability, is the degree to which...

  • Pseudoscience
    Pseudoscience
    Pseudoscience is a claim, belief, or practice which is presented as scientific, but which does not adhere to a valid scientific method, lacks supporting evidence or plausibility, cannot be reliably tested, or otherwise lacks scientific status...

  • Scientific method
    Scientific method
    Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of...

  • Tautology
    Tautology (logic)
    In logic, a tautology is a formula which is true in every possible interpretation. Philosopher Ludwig Wittgenstein first applied the term to redundancies of propositional logic in 1921; it had been used earlier to refer to rhetorical tautologies, and continues to be used in that alternate sense...

  • Testability
    Testability
    Testability, a property applying to an empirical hypothesis, involves two components: the logical property that is variously described as contingency, defeasibility, or falsifiability, which means that counterexamples to the hypothesis are logically possible, and the practical feasibility of...



External links

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