# Re: st: interpretation of interaction terms

 From Shehzad Ali To jose.de-sousa@univ-paris1.fr Subject Re: st: interpretation of interaction terms Date 16 Dec 2008 11:09:49 +0000

```Thank you, Jose. This is very helpful.

On Dec 16 2008, Jose de Sousa wrote:

```
```Wooldridge  Introductory Econometrics
Sorry for the misspelling.
Best
Jose

```
```Thanks, Rene and Dave. Semi-elasticity explanation makes good sense.
Please feel free to share any references if you get a chance.

On Dec 15 2008, René Geppert wrote:

```
In an all linear specification, regression coefficients are usually interpreted as marginal effects. Accordingly, in a log-log-specification, regression coefficients can be thought of elasticities. And for a lin-log-model, hence, the coefficient represent something like semi-elasticities.
```
-René

David Airey schrieb:
```
Yes, but I think the basic understanding or interpretation of regression coefficients for continuous or binary variables is not altered when a variable has been log transformed. It is true that interactions can be present or absent depending on whether or not a variable has been transformed, because interactions are scale dependent.
```
-Dave

On Dec 14, 2008, at 7:31 PM, Shehzad Ali wrote:

```
```Hi,

```
1. Coefficient on an interaction term for a dummy and log-transformed variable in an OLS model when the dependent variable is in natural units or is also log-transformed
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```
2. Coefficient on an interaction term for an untransformed continuous and log-transformed variable in an OLS model when the dependent variable is in natural units or is also log-transformed
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```
3. Coefficient on an interaction term between a dummy and log-transformed variable in a probit regression
```
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