What are the tests to perform to see if a set of returns data is suitable for a GARCH model? If returns data shows volatility clustering does that mean GARCH is suitable? Do you need to perform Ljung-Box test on the data to see autocorrelations?
- Apply the tests (e.g., Ljung-Box, ARCH) to return data in an attempt to ’see if there is anything there’.
- A proposed volatility model (e.g., GARCH, or some other non-linear model) is estimated, and the tests (e.g., Ljung-Box, ARCH) applied to the standardized and squared standardized residuals in order to ’see what is left’.
- If the model under consideration is adequate, the standardized and squared standardized residuals need to be white noise.
You can test for heteroscedasticity (via Ljung-Box for example). If you succeed in rejecting the NULL hypothesis of homoscedasticity, then you can apply an Arch Model.