Problem with recoding a variable, based on two others

[Michael Duarte Goncalves]

Hello everyone,

I am struggling with a basic recoding process. Basically, I have a variable called working_c19 which takes value 1 if people were working at that time, and 0 otherwise. Now, I want to recode variable so that it is only defined for those who were working at baseline period, January 2020 (variable called workin_bl).

I tried the following, but do not provide me exactly what I want:

egen byte working_c19_adjusted = rowmax(working_bl working_c19)

But basically, When I have 0 in the baseline period, and 1 in the current period, I obtain 1 in my new generated variable working_c19_adjusted.
I want to have 1 for my new variable only when both contain the value of 1.

Thank you in advance for your help.
Best,

Michael

[Carlo Lazzaro]

MIchael:
could you please share an example/excerpt of your dataset via -dataex-?. Thanks.

[Michael Duarte Goncalves]

Yes of course. Sorry, my bad.

* Example generated by -dataex-. For more info, type help dataex
clear
input byte(working_bl working_c19 working_c19_adjusted)
1 1 1
1 1 1
1 1 1
1 1 1
0 0 0
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
0 0 0
1 1 1
1 1 1
0 0 0
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
0 0 0
1 1 1
1 1 1
1 0 1
1 1 1
1 1 1
1 1 1
0 0 0
0 0 0
1 1 1
0 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 0 1
0 0 0
0 0 0
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
0 0 0
1 0 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 0 1
0 0 0
1 1 1
0 0 0
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
0 0 0
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
0 0 0
1 1 1
1 1 1
1 1 1
1 1 1
0 0 0
0 0 0
1 1 1
1 1 1
1 1 1
end
label values working_bl working_bl_val_lab
label def working_bl_val_lab 0 "Not working (Jan-Feb.2020)", modify
label def working_bl_val_lab 1 "Working (Jan-Feb.2020)", modify
label values working_c19 working_c19_val_lab
label def working_c19_val_lab 0 "Not working (Apr.2020)", modify
label def working_c19_val_lab 1 "Working (Apr.2020)", modify

I have put in bold some cases.
Thank you so much for your help.

Best,

Michael

[Nick Cox]

It is the row minimum you want as then the desired result will be 1 if and only if both variables are 1. For that egen has a function rowmin(varname1 varname2) and you can also use the standard function min(varname1, varname2)

However, watch out as the minimum of 1 and missing will be returned as missing. Depending on what you want to happen with missings, a suitable definition might be

gen wanted = cond(missing(varname1, varname2), ., min(varname1, varname2))

or

gen wanted = cond(!missing(varname1, varname2), min(varname1, varname2), .)

or

gen wanted = min(varname1, varname2) if !missing(varname1, varname2)

or

gen wanted = varname1 == 1 & varname2 == 1 if !missing(varname1, varname2)

[Michael Duarte Goncalves]

Hello Nick,

Thank you so much. I am using the last option:

 gen wanted = varname1 == 1 & varname2 == 1 if !missing(varname1, varname2)

And it works perfectly well.
Best,

Michael