90 likes | 216 Views
Econ 201. David Kim 3.23.2011. Heterogeneous Autoregressive (HAR) Class of Models. Represent expectation of future variance if all non-variance data is ignored Recently, it has been found that, when forecasting variance, simple models often outperform more sophisticated parametric models
E N D
Econ 201 David Kim 3.23.2011
Heterogeneous Autoregressive (HAR) Class of Models • Represent expectation of future variance if all non-variance data is ignored • Recently, it has been found that, when forecasting variance, simple models often outperform more sophisticated parametric models • Use averaged future RV as dependent variable and use averages of past values of variance measures as independent variables
HAR-RV • Multi-period normalized realized variation over h discrete periods • HAR-RV model • 1, 5 and 22 are used • Refer to daily, weekly and monthly frequencies • Associated with long-memory models
HAR-RV-CJ • Regression of RV on the lagged averaged normalized continuous and jump components
HAR-RV-RAV • Shown to be superior to HAR-RV and HA-RV-CJ • Realized absolute value (RAV) is substituted in as the regressor for realized variation
HAR-RV-RAV (cont’d) • Advantage of using RAV • Highly robust to jumps and sampling error • Jumps do not affect RAV asymptotically • RAV is in different units than RV
Combined Forecasts • HAR-RV-CJ with IV • HAR-RAV with IV
Robust Regression vs. OLS Estimation Methods • Robust method consistently outperformed OLS method over all models and time periods • Offers way to mitigate effects of confounding factors • Robust estimation has three goals • Good efficiency for assumed model • Small deviations from model assumptions should not have small effect on performance • Larger deviations from model should not ruin the model • Robust regression may be better at forecasting variance • Achieves estimates that are closer to the original model
To do: • More focus on out-of-sample forecasting results