Tell Stata to ignore missing values when adding variables

[Vasilis Tentolouris]

I want to create a new variable in Stata, that is a function of let's say 3 different variables, A, B and C, like so:
gen new_var = ((A)/3) + ((B)/2) + ((C)/4)
All observations have missing values for one or two of the variables, but that is not relevant to what I am trying to do. When I run this command, all it generates are missing values, because no observation has values for all 3 of the variables. I want STATA to complete the function and treat missing variables as 0 in the function. Is that possible with a simple command, without generating new dummy variables?
Many thanks.

[Brendan Cox]

The -cond()- function seems to be the (or at least a) way to go (though I look forward to seeing what other users come up with):

gen x = cond(missing(a), 0, a/3) + cond(missing(b), 0, b/2) + cond(missing(c), 0, c/4)

E.g.,

clear all
input a b c
9 10 8
6 . 12
3 . .
end

gen x = cond(missing(a), 0, a/3) + cond(missing(b), 0, b/2) + cond(missing(c), 0, c/4)

li

[Nick Cox]

Brendan gives good advice. In addition, if missings are really to be regarded as zeros, then mvencode beckons.

[daniel klein]

I want STATA to complete the function and treat missing variables as 0 in the function. Is that possible with a simple command, without generating new dummy variables?

Just replace the missing values with 0 then. Like

recode A B C (missing = 0) , prefix(new_)

I wonder, however, what the result might mean. Usually it is not a good idea to replace some unknown value (missing) with a value without accounting for the uncertainty associated with this change. I trust you know what you are doing.

Best
Daniel

[Vasilis Tentolouris]

Thanks a lot, this worked really nicely, very useful!

[Co Ar]

How do I generate var X that takes the row mean and ignores the missing?

[Co Ar]

what if I need to gen var X that takes the row mean and ignores the missing?

[Marcos Almeida]

You may wish to type - help egen - and check the aptly named -rowmean - option.

[cris layvar]

you can also try this:
use the egen commnand
and then use rowtotal, add all your variables, and then so a ,missing
such as:

egen WTP = rowtotal(FFWTP CFWTP ITWTP BWTP), missing

thanks.

C

[Francis Charles]

Hi, iam using endogenous switching regression in a panel data setting,my concern is,could you help me with commands on the same,i am trying to read but i have not gotten the concept well.thanks

[Nick Cox]

Francis: Your topic

Endogenous switching regression in a panel data setting

has nothing whatsoever to do with this thread, so you should consider starting in a new thread with a title like that. That said, posts of the form "I need to understand X" are less likely to be answered than concrete, specific questions showing code.

[Therersa Mens]

Hi,

I have a similar question. How can I apply excel COUNTA function in stata. In other words, how do I count all non empty cells in stata and generate a new variable that has the count of all non empty cells?

[Nick Cox]

I wouldn't assume that experienced Stata users here know much about MS Excel. But perhaps type

help egen

for its count() function.

[Therersa Mens]

Thank you for the response. I'll look at the count () function

[Latoya Sundack]

Dear Statalist

I have a total of 5600 observations for children who were able to get vaccinated (5000 yes, 600 no), however when generating the dummy for vaccines, it is capturing missing values for the entire dataset. I have a total of 7000 Wazs observations, as such the dummy is assuming 2000 no (i.e the 600 and the 1400 missing observations) . Is there a way to generate the dummy to only take into consideration the 5600 vaccinated observations?

gen Vacc =1 if Immu==1

replace Vacc=0 if mi(Vacc)

Thanks for your help.

Kind Regards!