Ventana software support forum

Thanks Tomfid. If it's possible, would you be willing to take a look at the model and make me some simple suggestions? There is a lot of floating errors and I'm getting frustrated with it. The constants (retention time, event fading time, etc.) do not seem similar across the drivers and I'm worrying...

Thanks a lot. I will take a look at those parameters across the drivers.

Thank you so much for your help Tom! I actually have more drivers that I can add. So, if I fit the model to all the drivers' data, what do you suggest to validate the model, especially since the model is fitted to a set of drivers?. Should I compute the R-statistics for each driver and average acros...

What are your thoughts about sample size for my work? Since I'm trying to calibrate per driver, should I be concerned about sample size?
What are the metrics to make the model believable?

Thanks for all your help. The file was probably corrupted. I deleted the file and downloaded a file posted here. I was trying to calibrate errors/mile since calibrating one variable provided me a good fit before. But I didn't get good results. 1) Do you think I still need a poisson distribution when...

And what should I do? Please, advise. I've restarted VENSIM several times and I'm not even able to do a simple run.
Thanks

sorry I forgot to attach the model. I'm unable to reset it to start the calibration over

I'm still getting the same warning after changing the weight to 1. Let me try this and see what happens. Instead of calibrating 2 measures (errors and monthly driving) per driver, I think I will calculate error/mile and calibrate that variable. I don't know if you will be willing to reset this model...

First of all, thank you a lot. The weight did really improve the model fit for both measures per driver. I have some floating errors, also the model did not capture at all 1 driver. I don't know if I still need to refine the weight or if there is something I need to do. Also some of the initial cond...

Thanks so much for the explanation!

Also, how can I reset a simulation? I mean if I want to start over.
I wanted to do a simple run; I clicked on "simulate" and I got this attached message. I was not trying to open data.vdf
Thanks

I mean 2 different measures per driver (driving errors and monthly driving). Probably I need different scales for the 2 variables. Should I use a scale of 1 for driving errors and 1,000,000 for monthly driving like you suggested?

Thanks for releasing the VENSIM 7 version.
There is a good fit when one variable is calibrated; however when 2 variables are simultaneously calibrated, the fit does not look good. What do you suggest/recommend when that happens?
Thanks for all your help

Thanks for your help.
I'm very hopeful that the newer version of VENSIM will be released tomorrow. Otherwise, you just have to help me again with the user-defined poisson distribution

Thanks for your input. The thing is the model provides a better fit for drivers with high errors and a poor fit for those with low errors, especially at start-up. Don't you think this phenomenon could be due to the wrong distribution used? My guess the distribution would approximate a normal distrib...

Thanks. From your experience, do you think the Poisson/binomial distribution can improve the model fit? Or is it a problem with the model structure?
I appreciate your input

Is the newer version of Vensim out?

Thanks so much. I know the theoretical concepts behind normal distribution, poisson distribution, binomial distribution, etc. My issue is the practical aspect of these concepts ie how to restructure my model in order to calibrate my model using poisson distribution. If you are going to release the n...

I'm still not able to do this thing. You mentioned that a new version of VENSIM with poisson distribution built-in was going to be released 2 weeks ago. Is the new version out yet? What do you mean by replacing MODEL and DATA variables with modeled and data events? I have a model variable called &qu...

Thanks. I've created your structure. Please, find attached the model. What's the next step?

I don't see any options of connecting the MODEL and DATA variables

Thanks so much.
I don't know what I should expect to see after I paste the structure into my model. But attached is what I got. What should I do next?

Thanks for all your help.
Could you help me with the steps to copy the structure and paste into my model? I've tried to copy and paste, but it did not work

Could you please take a look at the model and help me with the poisson distribution? You could also lay out the different steps to apply the poisson distribution
Thanks

I'm still not sure I understand how to do this. I honestly don't know what I'm doing by copying your structure into mine, so I'm confused here. I have attached both your model and mine. Could you please just set up the poisson distribution into my model for me so that I can directly use it? Thanks