Table of Contents

## What is the Hausman test Stata?

hausman is a general implementation of Hausman’s (1978) specification test, which compares an estimator ̂θ1 that is known to be consistent with an estimator ̂θ2 that is efficient under the assumption being tested.

## What does the Hausman test show?

The Hausman Test (also called the Hausman specification test) detects endogenous regressors (predictor variables) in a regression model. Endogenous variables have values that are determined by other variables in the system.

**What does Sigmamore mean?**

help hausman- gives you the following explanation of this option: “sigmamore allows you to specify that the two covariance matrices used in the test be based on a common estimate of disturbance variance (sigma2); the variance from the more (fully) efficient estimator.

### How do you choose between pooled OLS and fixed effects?

According to Wooldridge (2010), pooled OLS is employed when you select a different sample for each year/month/period of the panel data. Fixed effects or random effects are employed when you are going to observe the same sample of individuals/countries/states/cities/etc.

### What is Hausman’s test?

Remarks and examples stata.com hausman is a general implementation of Hausman’s (1978) speciﬁcation test, which compares an estimator b 1 that is known to be consistent with an estimator b 2 that is efﬁcient under the assumption being tested. The null hypothesis is that the estimator b 2 is indeed an efﬁcient (and consistent)

**Is Stata 6 relevant for the Hausman specification test?**

It is not relevant for Stata 6, which includes the hausman command to perform the Hausman specification test. Stata 5: How do I test endogeneity? How do I perform a Durbin–Wu–Hausman test?

#### What is the augmented regression test (DWH)?

Davidson and MacKinnon (1993) suggest an augmented regression test (DWH test), which can easily be formed by including the residuals of each endogenous right-hand side variable, as a function of all exogenous variables, in a regression of the original model. Back to our example, we would first perform a regression

#### Can We reject the null hypothesis in the Hausman test?

Here the 2statistic is actually negative. We might interpret this result as strong evidence thatwe cannot reject the null hypothesis. Such a result is not an unusual outcome for the Hausman test,particularly when the sample is relatively small-there are only 45 uninsured individuals in thisdataset.