Creating quartiles using loop for 25 continuous independent variables

[Anteneh Assefa]

Any suggestion how to fix this loop ?
I am trying to create quartiles for 25 continuous independent variables for use in logistic regression in order to compare the lowest quartile with highest quartile?

[Dennis Lund Hansen]

what kind of error message do you get?

I can not see, that the part after the comma i documented in the manual.
Perhaps something like:

foreach x of local `consentrations' {
    foreach n of numlist 25 50 75 100 {
        centile(`x'), c(`n')
       return list
       local q`n' = `r(c_1)'
    }
}

macro dir

[Joro Kolev]

You should report what Stata returned to you when you tried to execute the loop.

You obviously have errors in the syntax if -centile-.

And it is easier for me to write this from scratch than to fix what you have. Something like this:

foreach x in `concentrations' {
xtile quartile`x' = `x', nq(4)
}

[Nick Cox]

Several bugs there, starting with trying to use local macros that don't exist. But the big picture is that to create quartile-based bins, you should use a different command.

foreach x of local concentrations { 
    xtile quartile_`x'=`x',  nq(4) 
}