Thanks so much.
John
On Tue, Mar 17, 2009 at 6:03 PM, Matt Spittal
<[email protected]> wrote:
> Dear John,
>
> The command -reshape- is one way to tackle this problem. The trick that
> often catches me out is the naming of the y variable -- it needs to have a
> number at the end to signify the wave (e.g. y1, y2, ..., yn).
>
> Using your example:
>
> clear
> input patientid y_first y_second days_betw
> 299729 0 0 64
> 295861 0.17 0.08 63
> 292641 0.15 0.5 69
> end
>
> We then rename the y variable
>
> rename y_first y1
> rename y_second y2
>
> And then use the -reshape- command
>
> reshape long y, i(patientid) j(wave)
>
> Note that you can convert a dataset from long format to wide format with
> -reshape wide-. Finally, I noticed that you want the variable days_betw to
> be set to zero if this is the first measurement.
>
> replace days_betw = 0 if wave == 1
>
> See -help reshape- for more information on this command.
>
> -- Matt
> [email protected]
>
>
> On 18/3/09 11:37 AM, "john metcalfe" <[email protected]> wrote:
>
>> Dear Statalist,
>> Forgive me if this is too elementary of a question, but I have a
>> longitudinal data set in Format A below upon which I would like to
>> perform linear mixed effects regression (y on days_b grouped by
>> patientid). Is there an easy way to convert the data to Format B?
>> Many thanks,
>> John
>>
>> Format A: (current)
>> patientid y_first y_second days_betw
>> 299729 0 0 64
>> 295861 0.17 0.08 63
>> 292641 0.15 0.5 69
>>
>> Format B: (desired)
>> patientid y days_betw
>> 299729 0 0
>> 299729 0 64
>> 295861 0.17 0
>> 295861 0.08 63
>> 292641 0.15 0
>> 292641 0.5 69
>> *
>> * For searches and help try:
>> * http://www.stata.com/help.cgi?search
>> * http://www.stata.com/support/statalist/faq
>> * http://www.ats.ucla.edu/stat/stata/
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
