Solved – What’s the minimum sample size required to do a time series analysis

Question

I'd like to know the minimum number of monthly data points required to do time series analysis with the seasonality effect in forecasting.

I read some articles & they were saying that 50 or 60 data points are sufficient.
Is that the really minimum? Are there any trustful documentation which can be used as literature in this problem?

I'd be grateful if anyone can help.

Thank you.

Answer 1

Hanke and Wichern, chapter 3, page 80 ( http://www.amazon.com/Business-Forecasting-Edition-John-Hanke/dp/0132301202 ) recommend a minimum 2xs to 6xs depending on the method (where s is the seasonal period, so s=12 for monthly data). 50 data points would be 50/12 = 4 years of data.

But it depends on the regularity of the data. If the seasonal pattern is quite regular, 3 years is OK.