How to declare a time series of weekly data?

Question

I have a question regarding declaring my dataset as a time series. I have weekly historical data of demand of a certain product. Every week is labeled as 201401, 201402, up to the current month 201937.

The problem arises once I declare the set as ts <- ts(data, start=2014, frequency=52). Because every year consists of 365.25 days, in my set I have a week 201553. So from week 201601, every week is basically a week later, which causes problem when finding seasonality patterns.

Do I have to delete week 201553 or what is the appropriate continuation?

Answer 1

If you set frequency=365.25/7, things should work out fine.

References

• https://otexts.com/fpp2/ts-objects.html
• https://www.rdocumentation.org/packages/stats/versions/3.6.1/topics/ts (interestingly, the trick with frequency=52.17857 is not mentioned here)
• http://manishbarnwal.com/blog/2017/05/03/time_series_and_forecasting_using_R/