Reshape from wide to long, error

[Chiara Pastore]

Good morning,

I am using reshape on Stata 14. I am trying to convert my data from wide to long. I have data from a choice experiment, and each one of the 60 choice variables is called base_choice_n_ , where n is a number from 1 to 60.

Now, the code I am using is

 reshape long base_choice_, i(id) j(question_number)

but an error message comes up, saying that question_number (my j variable) contains all missing values. Any advice about this matter would be greatly appreciated!

Kind regards,

Chiara Pastore

[Joseph Coveney]

You can use the string option to the reshape command, but that will give you string values for your question_number variable, and I believe that's not what you want. Instead, you should rename your variables first in order that they have a numeric suffix. See below (begin at the "Begin here" comment).

.ÿversionÿ14.1

.ÿ
.ÿclearÿ*

.ÿsetÿmoreÿoff

.ÿquietlyÿsetÿobsÿ2

.ÿgenerateÿbyteÿidÿ=ÿ_n

.ÿforvaluesÿiÿ=ÿ1/6ÿ{
ÿÿ2.ÿÿÿÿÿÿÿÿÿgenerateÿbyteÿÿbase_choice_`i'_ÿ=ÿ0
ÿÿ3.ÿ}

.ÿ
.ÿ*
.ÿ*ÿBeginÿhere
.ÿ*
.ÿcaptureÿnoisilyÿreshapeÿlongÿbase_choice_,ÿi(id)ÿj(question_number)
variableÿquestion_numberÿcontainsÿallÿmissingÿvalues

.ÿrenameÿÿbase_choice_*_ÿÿbase_choice_*

.ÿreshapeÿlongÿbase_choice_,ÿi(id)ÿj(question_number)
(note:ÿjÿ=ÿ1ÿ2ÿ3ÿ4ÿ5ÿ6)

Dataÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿwideÿÿÿ->ÿÿÿlong
-----------------------------------------------------------------------------
Numberÿofÿobs.ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ2ÿÿÿ->ÿÿÿÿÿÿ12
Numberÿofÿvariablesÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ7ÿÿÿ->ÿÿÿÿÿÿÿ3
jÿvariableÿ(6ÿvalues)ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ->ÿÿÿquestion_number
xijÿvariables:
base_choice_1ÿbase_choice_2ÿ...ÿbase_choice_6->base_choice_
-----------------------------------------------------------------------------

.ÿ
.ÿexit

endÿofÿdo-file


.

[Richard Williams]

So, you have variables with names like base_choice_37_, base_choice_42_? If so, I have a feeling the trailing underscore may be causing problems. Instead try names like base_choice_37, base_choice_42.

[Chiara Pastore]

Dear Joseph and Richard,

Thank you for your reply! Problem was solved by renaming the variables as you suggested.

Kind regards