Dear Stata Members
I need a help with respect to truncation and how operationally it is different from removing observations and winsorizing observations. Please note the following remarks

ETR is defined as Income taxes paid (TXPD) divided by pretax income (PI). Firms are required to have a positive denominator, and ETR is truncated to the range [0,1]

Code:
Can we do something like this 
gen ETR=TXPD/PI
replace ETR==. if PI<0
drop if ETR>1
drop if ETR<0
.
However, all inferences are unchanged if we winsorize ETRs rather than truncating
I have used winsor2 by Nick Cox but I am not sure how to use it here as there are no percentiles involved.

Can someone help me here