How to check between several datasets which IDs go out or enter in the sample?

[Michael Duarte Goncalves]

Hi everyone,

I have a question to ask you please:

I have several datasets about electricity consumption in Spain, from January 2021 up to November 2023. My aim is:

1. I'd like to see which IDs leave my sample and which return. For example, I'd like to see whether, in February 2021, any IDs have already left my sample, or any new ones have come in.
2. I would like to do that for all my monthly files, from January 2021 to November 2023, please. These monthly data (from January 2021 to November 2023) contain household IDs.

Contracts IDs are located in another dataset. This dataset contains some contracts that began well before January 2021 (May 2011).

Below is an example for January 2021 (Dataset 1), and my dataset which contains contracts IDs in addition to households IDs (Dataset 2):

Dataset 1:

* Example generated by -dataex-. For more info, type help dataex
clear
input long(id fecha_consumo)
1001 20210101
1001 20210102
1001 20210103
1001 20210104
1001 20210105
1001 20210106
1001 20210107
1001 20210108
1001 20210109
1001 20210110
1001 20210111
1001 20210112
1001 20210113
1001 20210114
1001 20210115
end

• id is the variable for households IDs.
• fecha_consumo is the variable representing the date in which the electricity consumption was registered.

Dataset 2:

* Example generated by -dataex-. For more info, type help dataex
clear
input long(id idcontrato) double(date_contract_start date_contract_end)
1001    1001 18887 21700
1001  451697 21701 22431
1001 1236132 22432 22645
1001 1730454 22646 22676
1001 2082075 22677 22735
1001 2172904 22736 23010
1001 2872183 23011 23069
1001 3107888 23070     .
1005    1005 18800 21639
1005  420392 21640 21651
1005  432684 21652 22066
1005  720923 22067 22431
1005 1124767 22432 22456
1005 1288758 22457 22645
1005 1742918 22646 22676
end
format %td date_contract_start
format %td date_contract_end

• id is the variable for households IDs.
• date_contract_start is the variable representing the date in which the contract starts for a given household.
• date_contract_end is the variable representing the date in which the contract ends for a given household.

Could someone help me with this please? Thank you so much in advance.
Michael