Hi everybody
I have a panel data with 3 variables: year, country and product.
for each year I have 92 countries and 784 products, without any missing or duplicating data. so because of 3 dimensions, when I used "xtset country year" I got this massege: "repeated time values within panel". Therefore I want to Group country and product. can anybody help me about this?
I will appreciate any help
Nava