Sorting issue when sort is expanded by a variable

[Oscar Weinzettl]

Hello,

I have an issue running the following command

sort id _mi_m survey expectation gift_received

bys id _mi_m: gen treatment=0 if (expectation==2 & f.gift_received==2 & gift_total < 50000000) | (l.expectation==2 & gift_received==2 & gift_total < 50000000)

If I do this, it tells me error (5) not sorted. I can and have run this code without any issue without the _mi_m variable. However, my data uses multiple imputations and if I don't sort those my results are not fully correct as far as I understand it. So I want to expand my sort list to include the imputation observation variable to make sure those are sorted too. Yet this gives me an error. What have I done wrong or what am I missing?

* Example generated by -dataex-. To install: ssc install dataex
clear
input int id byte(_mi_m survey expectation gift_received)
 27 0 2 1 2
 27 1 2 1 2
 27 2 2 1 2
 27 3 2 1 2
 27 4 2 1 2
 27 5 2 1 2
 36 0 1 2 1
 36 0 2 2 2
 36 1 1 2 1
 36 1 2 2 2
 36 2 1 2 1
 36 2 2 2 2
 36 3 1 2 1
 36 3 2 2 2
 36 4 1 2 1
 36 4 2 2 2
 36 5 1 2 1
 36 5 2 2 2
 67 0 1 2 1
 67 0 2 2 1
 67 1 1 2 1
 67 1 2 2 1
 67 2 1 2 1
 67 2 2 2 1
 67 3 1 2 1
 67 3 2 2 1
 67 4 1 2 1
 67 4 2 2 1
 67 5 1 2 1
 67 5 2 2 1
 86 0 1 2 1
 86 0 2 2 2
 86 1 1 2 1
 86 1 2 2 2
 86 2 1 2 1
 86 2 2 2 2
 86 3 1 2 1
 86 3 2 2 2
 86 4 1 2 1
 86 4 2 2 2
 86 5 1 2 1
 86 5 2 2 2
 92 0 1 2 2
 92 0 2 2 2
 92 1 1 2 2
 92 1 2 2 2
 92 2 1 2 2
 92 2 2 2 2
 92 3 1 2 2
 92 3 2 2 2
 92 4 1 2 2
 92 4 2 2 2
 92 5 1 2 2
 92 5 2 2 2
128 0 1 2 2
128 0 2 2 2
128 1 1 2 2
128 1 2 2 2
128 2 1 2 2
128 2 2 2 2
128 3 1 2 2
128 3 2 2 2
128 4 1 2 2
128 4 2 2 2
128 5 1 2 2
128 5 2 2 2
130 0 1 1 1
130 1 1 1 1
130 2 1 1 1
130 3 1 1 1
130 4 1 1 1
130 5 1 1 1
178 0 1 2 1
178 1 1 2 1
178 2 1 2 1
178 3 1 2 1
178 4 1 2 1
178 5 1 2 1
303 0 1 1 2
303 1 1 1 2
303 2 1 1 2
303 3 1 1 2
303 4 1 1 2
303 5 1 1 2
484 0 1 2 1
484 0 2 2 2
484 1 1 2 1
484 1 2 2 2
484 2 1 2 1
484 2 2 2 2
484 3 1 2 1
484 3 2 2 2
484 4 1 2 1
484 4 2 2 2
484 5 1 2 1
484 5 2 2 2
594 0 1 1 1
594 0 2 2 2
594 1 1 1 1
594 1 2 2 2
end

[Nick Cox]

The use of F. and L. operators presupposes a sort on whatever you told tsset or xtset are panel identifier and time variables. Your prior sort seems at odds with that.

[Oscar Weinzettl]

So basically I either use mi xtset, which I am using, or I use sort "_mi_m" but not both? Do I understand that correcty?