An Open-model Forecast-error Taxonomy.

We develop forecast-error taxonomies when there are unmodeled variables, forecast ‘off-line’. We establish three surprising results. Even when an open system is correctly specified in-sample with zero intercepts, despite known future values of strongly exogenous variables, changes in dynamics can...

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Bibliografiska uppgifter
Huvudupphovsmän: Hendry, D, Mizon, G
Materialtyp: Working paper
Språk:English
Publicerad: Department of Economics (University of Oxford) 2011
Beskrivning
Sammanfattning:We develop forecast-error taxonomies when there are unmodeled variables, forecast ‘off-line’. We establish three surprising results. Even when an open system is correctly specified in-sample with zero intercepts, despite known future values of strongly exogenous variables, changes in dynamics can induce forecast failure when they have non-zero means. The additional impact on forecast failure of incorrectly omitting such variables depends only on shifts in their means. With no such shifts, there is no reduction in forecast failure from forecasting unmodeled variables relative to omitting them in 1-step or multi-step forecasts. Simulation illustrations confirm these results.