How to count persistent value for each group in panel data

[Martina Orlovic]

Hi all,

I have an issue with data counting, so hopefully someone can help me. I have converted the data in long, looks like this

ID Wave Percentage
1 1 10%
1 2 20%
1 3 20%
1 4 20%
2 1 .
2 2 20%
2 3 30%
3 4 40%
3 1 .
3 2 .
3 3 30%
3 4 40%

I would like to count how many participants across waves had persistent percentage above e.g. 20%?

Thank you!

Best wishes,
Martina

[Fei Wang]

Martina, if a participant has a missing percentage in some wave but all the non-missing percentages are above 20%, does the participant have a persistent percentage? If yes, please refer to the first code; if no, then the second code.

reshape wide Percentage, i(ID) j(Wave)
egen perc_min = rowmin(Percentage*)
gen persist = perc_min > 0.2 & perc_min < .
count if persist

reshape wide Percentage, i(ID) j(Wave)
egen perc_min = rowmin(Percentage*)
egen perc_miss = rowmiss(Percentage*)
gen persist = perc_min > 0.2 & !perc_miss
count if persist

[Martina Orlovic]

Thank you Fei for your kind help!