Econometrics: one step ahead forecast - page 94

 
faa1947:

Don't get sidetracked.

Highlight the deterministic component. What about the residual? We check again for the deterministic component. The cause is old. Get to the noise. Get the noise without the deterministic component, we can reason.


For non-stationary series, this deterministic component will change a lot over time. Adaptive methods must be applied to predict

 
Demi:


For non-stationary series this deterministic component will change a lot in course of time. For forecasting, adaptive methods should be applied

If you look at the topic first, you will see details of the following idea and practical calculations for it.

Idea:

1. fit the model to the sample

2. forecast 1 step ahead

3. once the fact arrives, fit again on a shifted sample

4 forecast 1 step ahead again.

There was a table to the right of the model parameters (lags) and you can see that the model parameters change almost every time.

 
faa1947:

If you look at the topic first, you will see details of the following idea and practical calculations for it.

Idea:

1. fit the model to the sample

2. forecast 1 step ahead

3. When the fact arrives, fitting again on a shifted sample.

4 again forecast 1 step ahead.

There was a table to the right of the model parameters (lags) and you can see that the model parameters change almost every time.


So that's what it is - unsteadiness, damn it to the ground)))))

Nothing good can come out of it. All this adaptation to pseudo-stationarity is just shamanism. This series will still be non-stationary no matter how you rape it. Very strongly non-stationary or strongly non-stationary or weakly or strongly non-stationary - there are no reliable forecasting methods. All mathematical statistics are developed on the basis of stationarity and ergodicity hypothesis.

 
I wonder what ergodicity has to do with it. Explain it for me, Demi: perhaps I am used to understanding it in some other way.
 
Demi:


So that's what it is - non-stationarity, damn it to the ground)))))

Nothing good can come of it. All this reduction to pseudo-stationarity is shamanism. This series will still be non-stationary, no matter how hard you force it. Very strongly non-stationary or strongly non-stationary or weakly or strongly non-stationary - there are no reliable forecasting methods. All mathematical statistics are based on the hypothesis of stationarity and ergodicity.

There are totals for the profit factor greater than 1, but that's little consolation, as there were worse.

Don't want to get discouraged. Maybe a bad smoothing, maybe the wrong regressors? Or a wrong interpretation of the forecast? We need to look into it. That's what I opened a branch for.

 
faa1947: There was a table on the right with the model parameters (lags) and you could see that the model parameters changed almost every time.
And you still intend to stick with a model that is highly unstable in terms of the main parameters?
 

Mathemat:

I wonder what ergodicity has to do with it? Explain it for me, Demi: perhaps I'm used to understanding it in some other way.
If and only if the stochastic process is ergodic, the time or space series makes it possible to estimate the distribution function corresponding to both future and past values. Ergodicity provides a basis for treating past indicator values as a random sample from a homogeneous population of future values.

For ergodic processes, both the expectation, variance and autocorrelation function calculated from one realization will be the same for any other realization.

(Partial citation.)

If a series is non-stationary, therefore it is non ergodic.

 
Mathemat:
And you still intend to stick with a model that is highly unsustainable in the main parameters?
I'm not sticking to the model, I'm sticking to the metod
 

Demi: Тогда и только тогда, когда стохастический процесс является эргодическим

Well, firstly, these are all general words which I am already familiar with.

Secondly, looking at the quotation process as a set of realisations was not the point. The realisation is one, full stop. At least in econometrics.

Third, and most importantly: how can it be checked, ergodicity, if we can't make other possible realizations? (If we could do it, we could make an ideal tester, which would be able to check any TC for robustness one hundred percent, as we would have, roughly speaking, as much input data as needed, i.e. infinity).

faa1947: I'm not sticking with the model, I'm sticking with the metod.

OK, the question is the same, but to the method.

 
Mathemat:

OK, same question, but to the method.

There's nothing else I know of that's so well-developed
Reason: