# [R] Different ARCH results in R and Eviews using garch from tseries

Constantine Tsardounis costas.magnuse at gmail.com
Sun Dec 25 23:25:32 CET 2005

```Dear Sir,

First of all Happy Holidays!,...

I am writing to you because I am a bit confused about ARCH estimation.
Is there a way to find what garch() exactly does, without the need of
reading the source code (because I cannot understand it)?
In Eviews (the results at the end) I am getting different results than
in R (for those that have the program I do: Quick -> Estimage Equation
-> Method: ARCH -> y c x ->  GARCH:0 & ARCH:1 -> ARCH-M term: none.

and can be loaded in R with:

garch(summary(lm(y ~ x))\$resid^2, c(0,1))

What I am doing wrong? Because I want to check for ARCH(q) effect and
then estimate the final equations (Y on X, with the equation of the
error term)

Tsardounis Constantine
Student in Economics at University of Thessaly, Greece

Eviews results:
Dependent Variable: Y
Method: ML - ARCH
Date: 12/26/05   Time: 00:05
Included observations: 83 after adjusting endpoints
Convergence achieved after 16 iterations

Coefficient	Std. Error	z-Statistic	Prob.

C	0.005268	0.002442	2.157327	0.0310
X	0.947425	0.024682	38.38587	0.0000

Variance Equation

C	0.000456	8.55E-05	5.333923	0.0000
ARCH(1)	-0.041617	0.117458	-0.354311	0.7231

R-squared	0.941163	    Mean dependent var		0.016895
Adjusted R-squared	0.938928	    S.D. dependent var		0.086783
S.E. of regression	0.021446	    Akaike info criterion		-4.801068
Sum squared resid	0.036336	    Schwarz criterion		-4.684498
Log likelihood	203.2443	    F-statistic		421.2279
Durbin-Watson stat	1.503765	    Prob(F-statistic)		0.000000

```