Hi

I don't understand what do you mean exactily but I expecte you mean if there are other models belongs to Arch Garch famlily if so I will say :Yes. Such as Egarch TArcv.... ,

ARCH family is ofcourse different from GARCH families. But the question is when xontinue to develop different model such as E-GARCH, TGARCH, ......among others. How far have these model explain the nature of volatility often experienced in stock return. Also, does it mean developing robust model to communicate how taughtreally explain more on volatility predictions.

The research never stops to produce new econometric models

Do you think these models are unnecessary complications, even when these models never improved the understanding of volatility but patterns.

Hi

The development of a model from the Arch-Garch family to other models where new terms are added with different lag such as adding square error term to the lagged variance Ar model and then adding the interaction between the lagged variation and the lagged square errors of at different levels also when the logarithm of the terms is added will increase the representation of the estimated model to represent the volatality of variance of errors optimally.