In article <[EMAIL PROTECTED]>,
Taweewan Sidthidet <[EMAIL PROTECTED]> wrote:
> Everyone know about "turining poing" in forecasting?
> Can you anyone help me about how to calculate this turning point in
> Econometric Model?
> Thanking you in anticipation.
\\
A turning point could be considered as an "unusual value" whose impact
is to generate forecasts that may have a trend different from recent
actual valuues. For example an AR(2) process may predict up just as long
as recent values are "up" but as recent values lose their "upness" ( bad
english but colorful just the same ) the forecast could well point to an
assymptote or even downwards. This is a powerful feature of
stochastic models such as ARIMA which are developed based on the
evidented structure and behavior of the observed data rather than some
predetermined model form predicated on presumption ala many
econometric models.
Turning points may also arise as an unusual value which should not be
sanitized or cleansed but rather should be heeded. For example you might
see http://www.autobox.com/referenc.html for papers/articles/books on
this subject ...particularly
Tsay, R.S. (1986). "Time Series Model Specification in the Presence of
Outliers," Journal of the American Statistical Society, Vol. 81, pp.
132-141.
Wei, W. (1989). Time Series Analysis Univariate and Multivariate
Methods.
Redwood City: Addison Wesley.
Hope this helps .
Dave Reilly
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