Glossary of Scientific Terms

Accuracy

A measurement result is considered accurate if it is judged to be close to the true value.

Belief*

When the public hears the word “believe,” non-scientists think of a statement of faith or else a statement of uncertainty as in “I believe it will rain today, but I’m not certain.” When scientists say, “We believe” in the context of scientific research, it means that all the evidence collected so far supports this viewpoint and furthermore, opposing viewpoints have no evidence to support them. “Scientists believe” is basically analogous to non-scientists stating a fact that they know.

Data

Information, either qualitative or quantitative, that has been collected.

Causation**

One event is the result of the occurrence of the other event. This is also referred to as cause and effect. Beware: Just because two things occur together does not mean that one caused the other. Correlation** A statistical measure that describes the size and direction of a relationship between two or more variables. A correlation between variables, however, does not automatically mean that the change in one variable is the cause of the change in the values of the other variable. Example: Height and weight are correlated. Taller people tend to be heavier than shorter people. In contrast, both the price of gas and the number of Facebook users have gone up in the past years, but gas prices are not causing the number of Facebook users to increase.

Error

Margin of variability given the limits as to how precise you could possibly be.

Evidence

Data that has been shown to be valid.

Hypothesis

A proposal intended to explain certain facts or observations.

Peer review***

A peer review is an in-depth critique of assumptions, calculations, extrapolations, alternate interpretations, methodology, and acceptance criteria employed, and of conclusions drawn in the original work. Peer reviews confirm the adequacy of the work. Peer review is expert (including national/international perspectives on the issue), independent, external, and technical. Most importantly, peer reviews must be carried out by independent reviewers who are experts in the technical issues relevant to the projects under review. Such reviewers must be highly qualified and independent in order to evaluate credibly the scientific and engineering merit of the work

Precision

Precise measurements are ones in which there is very little spread about the average measured value. Precision depends only on the extent of random errors – it gives no indication of how close results are to the true value.

Prediction

A prediction is a statement suggesting what will happen in the future, based on observation, experience or a hypothesis.

Repeatable

A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results.

Reproducible

A measurement is reproducible if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained.

Theory*

For scientists, a theory is a complex construct of well-tested observations that describe some part of how the world works as well as predict how the world works. Scientific theories are not guesses or hunches.

True value

This is the value that would be obtained in an ideal measurement with no error.

Uncertainty

The limit of the sate-of-the-art knowledge given a complex system or not enough data. Also the interval within which the true value can be expected to lie, with a given level of confidence or probability, e.g. “the temperature is 20 °C ± 2 °C, at a level of confidence of 95 %.

Validity

Appropriateness of the investigative procedure to answer the question being asked. For example, an investigation to find out whether methane found in a water well was from drilling would not be valid if it did not check for other possible sources of the methane.

Valid conclusion

A conclusion supported by valid data, obtained from an appropriate experimental design and based on sound reasoning.

Resources

*Helen Quinn, “Belief and Knowledge – A Plea About Language,” Physics Today, January 2007

**Australian Bureau of Statistics

***Definitions from AQA  except for “peer review” which is adapted from the National Academies Press.