# What do you call the left hand side variables in a regression/classification?

If I have a regression or classification problem

y ~ x1 + x2 + ... + xn


I might call the xi the regressors or the predictors. But what do you call y?

The terms regressand and predictand are clunky, don't seem particularly standard, and have the disadvantage that they're very similar to the words for the right-hand-side variables (I'm going to be using these terms in type declarations and documentation for a program, so minimizing the potential for confusion is a priority).

Also, using regressor and regressand is inappropriate when you have a classification problem, rather than a regression.

Is there a commonly used term?

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I think the "response" or "outcome" variable are commonly used terms. –  Macro Aug 28 '12 at 15:27
What if you are using regression to do classification? –  jkd Aug 28 '12 at 15:56
'outcome' also seems fine for classification. Or try 'class' or 'category'. If you're really fitting regression models for classification purposes you should probably stop, and use a proper model instead ;-) –  conjugateprior Aug 28 '12 at 16:11
In regression it is also called the dependent variable or DV and the Xs are called the independent variables or IVs. However the independent variables do not have to be and usually are not statistical independent. –  Michael Chernick Aug 28 '12 at 16:14
@ConjugatePrior Is logistic regression considered a regression method? Since glm is a generalization of the linear model, cannot glm be considered regression too? –  jkd Aug 28 '12 at 16:44
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