topic Re: Imputation of missing values in SAS Programming

Imputation of missing values

deltaskipper — Sun, 02 Sep 2018 18:32:55 GMT

Problem statement: I have a data set flying which consist of variables:

[1]origin [2]destination [3]carrier [4]delay

Now I want to replace the missing value in variable delay with average delay on the specific route(source-destination) and carrier.

If i use proc stdize for imputation it replace the missing value with the average of variable delay which I dont want to do.

Any suggestion/help will appreciate.

My code :

proc stdize data=flight missing=mean reponly out=missing_flight;
var air_time;/* delay*/
by origin dest carrier notsorted ;
run;

It shows some warning :

WARNING: At least one of the scale and location estimators of variable air_time can not be computed. Variable air_time will not be

standardized.

After that I check my missing values in the output dataset missing_flight . It is still missing and imputation is not done.

what am I doing wrong here?

Re: Imputation of missing values

Reeza — Sun, 02 Sep 2018 17:43:01 GMT

Add a BY statement to PROC STDIZE to group by source/destination.

@deltaskipper wrote:

Problem statement: I have a data set flying which consist of variables:

[1]origin [2]destination [3]carrier [4]delay

Now I want to replace the missing value in variable delay with average delay on the specific route(source-destination) and carrier.

If i use proc stdize for imputation it replace the missing value with the average of variable delay which I dont want to do.

Any suggestion/help will appreciate.

Re: Imputation of missing values

PGStats — Sun, 02 Sep 2018 19:52:46 GMT

Maybe you misinterpreted what NOTSORTED means in the BY statement. NOTSORTED means that the data is grouped by the origin, dest, and carrier variables, but that they are not in ascending or descending order. Try sorting your data prior to calling STDIZE without the NOTSORTED keyword.

Re: Imputation of missing values

Reeza — Mon, 03 Sep 2018 01:13:40 GMT

FYI if you respond by editing your original post no one knows what was changed, what is new and it won’t come across as a new post. You’re better off replying than editing your original question.

Re: Imputation of missing values

deltaskipper — Mon, 03 Sep 2018 12:44:44 GMT

Yeah from next time. I keep this thing in mind.
And yes thanks for advice.

Re: Imputation of missing values

deltaskipper — Mon, 03 Sep 2018 12:45:18 GMT

Thats work.
Thank you for that