# correlation

## Origin of correlation

## Word story

Correlation has been in the English language since the 16th century. Its French cousin, corrélation, comes from Latin which literally means “restoring things together.” In English, we use it to describe a mutual relation between two things. Correlation is not to be confused with the word corollary, which is derived from an entirely different Latin root, corrollārium, a kind of ancient Roman gratuity, a “little something extra.”

In the 19th century, scholars of various disciplines adopted the term correlation to their specific areas of interest. In statistics, a correlation between two variables can be described as a numerical value. The words “positive,” “negative,” “strong,” and “direct” are often used as modifiers before correlation in this context. In the fields of biology and geology, researchers use correlation to help understand and describe various features of physiology and rock formations respectively. With the original meaning still in popular use, correlation is not just for mathematicians and scientists. Just be aware that if you casually mention correlation (in the general sense) to math enthusiasts, their initial responses might be to visualize a graph.

## Popular references

—Pearson correlation coefficient: a value between -1 and +1 that represents the relationship between two variables.

- "There's not a direct correlation between poverty and violence and conflict and terrorism."-Barack Obama in Strasbourg Town Hall American Rhetoric (delivered April 3, 2009)
- "Researchers compute correlation coefficients when they want to know how two variables are related to each other."-Timothy C. Urdan Statistics in Plain English (2005)
- "By the expression ‘Correlation of the Organs,’ is understood the state of mutual dependence of the organs, after their division of labor has been brought about by the process of evolution; each has its own particular function to perform, but the fulfilment of this function is not sufficient for its existence, since rather it would be unable to perform its own function without the aid it derives from the other organs."-Thomas H. Montgomery, Jr. Organic Variation as a Criterion of Development Journal of Morphology, Vol. XII (1897)
- "From correlation of the rock sequences exposed at different localities, geologists can reconstruct a geologic history over a billion years long."-Frank Press, et. al Understanding Earth (2004)

## Related Words for correlation

interrelationship, interaction, parallel, correspondence, interchange, reciprocity, relationship, complement, counterpart, correspondent, interdependence, analogue, alternation, match, interconnection, interrelation, pendant## Examples from the Web for correlation

### Contemporary Examples of correlation

Darwin called the same phenomenon the “correlation of growth” and geneticist today study what they call “pleiotropic effects.”

As a designer, Gianni was completely aware of that correlation.

Princess Diana, Kate Moss, Donna Karan, and More Reactions to Gianni Versace’s 1997 MurderThe Fashion Beast Team

July 15, 2014

Past research hints at a correlation between extent of brain injury following impact and the biomechanical forces at play.

The lack of correlation between saturated fat intake and heart disease risk still stands.

The correlation is especially robust in the lower grades, when students are in their formative years.

### Historical Examples of correlation

Yet we accept them as the best expression which we have of the correlation of forces or objects.

ParmenidesPlato

And the best way of getting this correlation is through community surveys.

College TeachingPaul Klapper

That is to say, in the nature of things the correlation could not have been otherwise.

Essays: Scientific, Political, & Speculative, Vol. IHerbert Spencer

So far we have only a superficial perception of this correlation.

Researches on CelluloseC. F. Cross

There is a correlation between the state of development of the teeth and of the foot.

Form and FunctionE. S. (Edward Stuart) Russell