Hi Sven
I am not sure
Brian J Revell
Professor Emeritus (Agricultural Economics)
Harper Adams University UK
Current Chair of Defra Economic ADvisory Panel
Former President Agricultural Economics Society

Tel: home 01952 728153  Mobile 07976 538712
Address: Orchard Croft, Vineyard Rd, Homer, Much Wenlock TF!3 6NG


On Wed, 28 Feb 2024 at 13:50, Sven Schreiber <sven.schreiber@fu-berlin.de> wrote:
Am 28.02.2024 um 09:37 schrieb Brian Revell:
There is an irritation in using the Forecast Function in Analysis in that it treats Panel data as a continuum between adjacent panel units in plotting by observation number sequence. So as illustrated below, there are 21 annual observations in Panel 1 ending in 2021. However the forecast funtion treats this as as a observation continuum from 1:21 to 2:01(year 2001) and plots an irritaing line between1:21 and 2:01......and similarly between all the adjacent 10 Panel Units. Is there anyway to suppress this joining line, as the forecast graph plots beautiful CI shaded areas.
The workaround is to transfer the data to Excel -but that does not provided a shaded 95% CI -which is clearly more elegant -only the ability to plot the Upper and lower CI bounds as lines..

Hi Brian,

I am running the forecast function via the Estimated Model  output/ /Analysis/Forecast in the GUI.  My aim is not to generate forecasts beyond time period 2021 but simply to produce a prediction for actual Y values (not mean) with associated 95% CI spread.  This works perfectly (see data section below). The graph however, as I said , seems to join the datapoints from adjacent panel data units i.e .it will add a line between observation 1:21 and 2:01 etc. for the dependent variable l_RSE (the number of returning adult salmon)  The graph of the prediction, acutal and CI joins inserts a line joining the final value of Y (ln RSE) in 1:21 to that of  2:01  , 2:21 to 3:01 et al..  .  The graph is generated by selecting 0 for the number of preforecast obsvns to graph and a tick in checkbox for show fitted values for preforecast range
            l_RSE          prediction    std. error     95% interval1:01            
1:01
1:02            
 1:03            
 1:04            
 1:05     7.184629
 1:06     7.034388     6.894189     0.282773     6.335766 - 7.452613
 1:07     6.697034     6.633725     0.282741     6.075366 - 7.192085
 1:08     6.632002     6.691674     0.282374     6.134040 - 7.249307
 1:09     6.411818     6.456549     0.284239     5.895231 - 7.017867
 1:10     6.661855     6.971589     0.285004     6.408761 - 7.534417
 1:11     6.635947     6.491402     0.283699     5.931152 - 7.051652
 1:12     6.670766     6.814620     0.282740     6.256262 - 7.372978
 1:13     6.526495     6.500384     0.282566     5.942371 - 7.058397        PANEL UNIT 1   -River No. 1
 1:14     7.074117     7.339223     0.289105     6.768296 - 7.910149
 1:15     7.193686     7.441791     0.285464     6.878053 - 8.005528
 1:16     6.944087     7.205822     0.283033     6.646886 - 7.764759
 1:17     6.601230     6.696775     0.283867     6.136192 - 7.257357
 1:18     6.556778     6.177856     0.285445     5.614156 - 6.741556
 1:19     7.309881     6.955872     0.283390     6.396231 - 7.515514
 1:20     6.963190     6.860621     0.283066     6.301620 - 7.419622
 1:21     6.729824     6.452257     0.284134     5.891148 - 7.013367
 2:01     6.952729
 2:02     5.905362
 2:03     7.029088     7.102234     0.295125     6.519420 - 7.685049
 2:04     7.018402     7.091428     0.286250     6.526138 - 7.656717
 2:05     6.964136     6.865752     0.286381     6.300206 - 7.431299
 2:06     6.498282     6.909504     0.286639     6.343447 - 7.475561
 2:07     7.304516     7.068966     0.289634     6.496995 - 7.640937
 2:08     6.805723     6.882406     0.288406     6.312860 - 7.451953
 2:09     6.725034     6.891609     0.286613     6.325603 - 7.457614
 2:10     6.887553     7.073868     0.288169     6.504789 - 7.642946Panel Unit 2   River No. 2
 2:11     6.855409     6.920967     0.288442     6.351349 - 7.490584
 2:12     6.927558     7.083822     0.286813     6.517421 - 7.650222
 2:13     6.908755     6.889174     0.286116     6.324149 - 7.454199
 2:14     7.604396     7.255976     0.287378     6.688459 - 7.823493
 2:15     7.282074     7.247741     0.288574     6.677862 - 7.817620
 2:16     7.522941     7.159051     0.286828     6.592620 - 7.725482
 2:17     6.526495     6.772668     0.290510     6.198966 - 7.346371
 2:18     6.891626     6.668582     0.288539     6.098773 - 7.238391
 2:19     7.988543     7.155666     0.287025     6.588847 - 7.722484
 2:20     6.556778     6.971224     0.293826     6.390974 - 7.551473
 2:21     6.226537     6.513208     0.288322     5.943828 - 7.082588
 3:01     5.476464
 3:02     5.129899
 3:03     6.016157     5.892951     0.292152     5.316006 - 6.469896

Hope that clarifies the issue.
Brian

______________________________________________________________________________


I tried to run a forecast on the grunfeld example panel dataset shipped with gretl. I restricted the sample to leave out the last two time periods, to save them for forecasting, and then estimated a trivial dynamic/reduced-form fixed-effects regression with "invest" as the dep. variable. (Let's ignore the Nickell bias issues for this example.) No contemporaneous variables, but in the model window under the Analysis menu the "Forecasts..." entry was still greyed out, so I couldn't cross-check what you described.

So, it would be helpful if you could describe how exactly and with what data you produced your forecasts.

thanks

sven

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