Hi Debraj,

Stata handles unbalanced data pretty easily. You need to tell Stata what your ID variable is and your year variable and then Stata will know that it is panel data and that the panel is unbalanced. I recommend you look into the xtset command and related commands, xtdescribe and xtsum, just to explore your data and see how Stata handles an unbalanced panel. For your econometrics the command will depend on the type of model you intend on using (e.g. xtreg for linear regression) but once you have told Stata that your data is panel and unbalanced (using xtset) that isn't really any more complicated than modelling with a balanced panel. It's just a matter of correct interpretation.

Thank you Joanne for your response.

I know that the xtreg shows the result that our panel is balanced or unbalanced, but I faced the problem that the Stata command ( xtreg country year) can't run, because, my time series in panel is started from 2006 in some countries and some have started from 2008. In this situation, If we put the time in all countries from 2006, there is highly chance to increase the missing value. If we delete 2006, 2007, there will be reduce the number of observation, so what is the solution to solve this problem ? If you response me, I will be grateful.

Hi Debraj,

I understand now. If you have panel observations for some countries that starts from 2006 but others that starts from 2008 you can only run your model starting from 2008. I understand your concern about losing the data from 2006 and 2007 but it's just a fact that you do not have data on some of your countries for those years, so if you want to run a model including all of the countries in your dataset you cannot use the data from 2006 or 2007. This isn't necessarily a big problem, you just need to explain that your model covers the period 2008 onwards because that is the timeframe where you have data on all countries of interest.

The degree to which it is a problem will also depend of the length of your panel too. How many years of data do you have if you exclude 2006 and 2007?

Hello Joanne

Thank you very much for your answer, . Before, I am searching way out to deal this issue. But now I become clear about my concern, I c an't run the stata in this situation. Am I right ? I have two option only, either I need to delete 2006 and 2007 for all countries or I am ready to accept to increase missing value.

Once again, thanks for your answer.

Yes. You don't need to delete 2006 and 2007. You can just add an if statement to your command to tell Stata not to include those years. Example: xtreg [variable list] if year>2007 (if you choose to exclude 2006 and 2007). You can always try both options (including 2006 and 2007, then excluding them) and look at the results from each, being aware of what those results mean in each case in terms of missing data.

Dear Joanne ,

Thank you very much for your brief suggestion.

Dear Joanne,

Good help.

Hope the issue is resolved.

Additionally, please take care of the number of cross section N and time components T in the selection of method of analysis.

Best wishes

Yes solve the problem, thank you all for your kind support

Be careful about the number of individuals (i) and the number of time periods (t).