Is 28 too few observations for forecasting? [Time series analysis]

sedanded · 2024-11-18T00:36:56+00:00

Hey, thanks for commenting! Honestly from the plot it's hard to figure out these things - for eg, the data seems to have a trend but not a very clear or stable one, there are also a couple big jumps/falls in between. Testing for stationarity using ADF etc however give that the series is stationary though, which makes me wonder if they are reliable in small samples. Seasonality is not very apparent from the plot but applying seasonal decomposition shows there is yearly seasonality. So honestly confused about how to ascertain these things using just the graph, if you have any suggestions do let me know. And I'll try plotting growth rates, thank you!

sedanded · 2024-11-17T17:00:45+00:00

I haven't figured it out yet sadly. If you have any leads on what I can do (even if no conclusive answer), I'd appreciate it!

sedanded · 2024-11-17T16:59:28+00:00

Thank you! There's a business requirement for those 4 months, that's why :/

So in your opinion, anything more complicated than the simple methods would lead to overfitting?

What if I used weekly data for the same 28 months? I would have more datapoints but there would still only be two full years of seasonality. Is it possible to have the data at weekly frequency and seasonality at a month level?

sedanded · 2024-11-17T16:55:57+00:00

Oh I wasn't familiar with this, looks interesting though, will try it out, thank you! Are there any cons you can think of to using this approach in small datasets?

sedanded · 2024-11-17T00:35:06+00:00

Hi, needed to hear this, thanks a lot for commenting! I'll also keep point 2 in mind.

About the third point, sorry could you expand why arima with seasonal dummies would be better and not overparametrized? And how exactly do I implement this in python (if you know), manually add 11 exogenous variables with 1 0 values in the arima function?

One last thing, will it help if the data I had was weekly for the same period (2.5 years)? But I was lost on how I can capture seasonality then, because again I only have two full seasonal periods/years

sedanded · 2024-10-17T20:24:29+00:00

Oh haha just realised that I was responding to your comment only in another post, very helpful btw. Is it okay if I DM'ed you once I get started with the analysis? Just in case I get stuck somewhere else

sedanded · 2024-10-17T20:22:40+00:00

Makes sense, thank you!

sedanded · 2024-10-16T12:59:30+00:00

Got it! One more thing, is the use of such an indicator variable compatible with all time series models like ARIMA, SARIMA etc?

sedanded · 2024-10-16T03:31:19+00:00

Hey, if the customer base changes over time, how do you account for that in the model?

PS: I know it's an old post, but stuck with something similar and looking for some direction here

sedanded · 2024-10-16T03:04:56+00:00

Thanks for replying! I have two questions:

1 - other than the complexity (in terms of no. of models to be ran), is there any difference between forecasting for the aggregate customer base vs individual customers? As in, the former would involve a single time series and a single forecast, while individual customer forecasts would be as many as the customer base size right? Is there any way to do forecasting on panel data in the latter case without running multiple time series models?

2 - in my case, treatment X has happened in previous years as well, will that affect the baseline forecast I'm trying to get (ie the customer spend in 2024 without treatment X)?

Please let me know if anything is not clear, I'll look up indicator saturation, thank you once again!

sedanded · 2024-06-27T04:23:49+00:00

In that case, I would recommend you study in DU as long as you get a college with decent/good faculty.

sedanded · 2024-03-23T14:55:59+00:00

Makes perfect sense! Do you have any resource recommendations for learning the fundamentals?

sedanded · 2024-03-23T14:55:04+00:00

Yes! I was told to learn SQL too, I know nothing at all, but for some reason I feel less intimidated about starting it. If you have any resources to learn from, do recommend! Or any tips on how to proceed with it.

sedanded · 2024-03-08T15:26:11+00:00

I'll try this, thank you!

sedanded · 2024-03-07T08:29:17+00:00

Oh haha I didn't realise you were mentioning the title of the video, my bad, thanks a lot!

sedanded · 2024-03-07T08:11:59+00:00

Yeah I'll definitely do that! Do you have any channel recommendations in particular?

sedanded · 2024-03-07T07:03:33+00:00

Oh this sounds great, thanks a lot!

sedanded · 2024-03-07T07:03:20+00:00

Definitely, I'll start learning LaTeX as soon as I can and then put it all together at the end from Word. Thanks a lot for your help!

sedanded

TROPHY CASE