# Correspond vs. Correlate - What's the difference?

### Wikipedia

• Correlate

In statistics, dependence or association is any statistical relationship, whether causal or not, between two random variables or bivariate data. In the broadest sense correlation is any statistical association, though in common usage it most often refers to how close two variables are to having a linear relationship with each other. Familiar examples of dependent phenomena include the correlation between the physical statures of parents and their offspring, and the correlation between the demand for a limited supply product and its price. Correlations are useful because they can indicate a predictive relationship that can be exploited in practice. For example, an electrical utility may produce less power on a mild day based on the correlation between electricity demand and weather. In this example, there is a causal relationship, because extreme weather causes people to use more electricity for heating or cooling. However, in general, the presence of a correlation is not sufficient to infer the presence of a causal relationship (i.e., correlation does not imply causation). Formally, random variables are dependent if they do not satisfy a mathematical property of probabilistic independence. In informal parlance, correlation is synonymous with dependence. However, when used in a technical sense, correlation refers to any of several specific types of relationship between mean values. There are several correlation coefficients, often denoted ρ or r, measuring the degree of correlation. The most common of these is the Pearson correlation coefficient, which is sensitive only to a linear relationship between two variables (which may be present even when one variable is a nonlinear function of the other). Other correlation coefficients have been developed to be more robust than the Pearson correlation – that is, more sensitive to nonlinear relationships. Mutual information can also be applied to measure dependence between two variables.

### Wiktionary

• Correspond (verb)

to be equivalent or similar in character, quantity, quality, origin, structure, function etc.

• Correspond (verb)

to exchange messages, especially by postal letter, over a period of time.

"I've been corresponding with my German pen pal for three years."

• Correlate (verb)

To compare things and bring them into a relation having corresponding characteristics

• Correlate (verb)

To be related by a correlation

• Correlate (noun)

Either of a pair of things related by a correlation; a correlative.

### Webster Dictionary

• Correspond (verb)

To be like something else in the dimensions and arrangement of its parts; - followed by with or to; as, concurring figures correspond with each other throughout.

• Correspond (verb)

To be adapted; to be congruous; to suit; to agree; to fit; to answer; - followed by to.

• Correspond (verb)

To have intercourse or communion; especially, to hold intercourse or to communicate by sending and receiving letters; - followed by with.

• Correlate (verb)

To have reciprocal or mutual relations; to be mutually related.

• Correlate

To put in relation with each other; to connect together by the disclosure of a mutual relation; as, to correlate natural phenomena.

• Correlate (noun)

One who, or that which, stands in a reciprocal relation to something else, as father to son; a correlative.

### Princeton's WordNet

• Correspond (verb)

be compatible, similar or consistent; coincide in their characteristics;

"The two stories don't agree in many details"

"The handwriting checks with the signature on the check"

"The suspect's fingerprints don't match those on the gun"

• Correspond (verb)

be equivalent or parallel, in mathematics

• Correspond (verb)

exchange messages;

"My Russian pen pal and I have been corresponding for several years"

• Correspond (verb)

take the place of or be parallel or equivalent to;

"Because of the sound changes in the course of history, an 'h' in Greek stands for an 's' in Latin"

• Correlate (noun)

either of two correlated variables

• Correlate (verb)

to bear a reciprocal or mutual relation;

"Do these facts correlate?"

• Correlate (verb)

bring into a mutual, complementary, or reciprocal relation;

"I cannot correlate these two pieces of information"