Re: st: time-series data identified by three variables

[Nick Cox <njcoxstata@gmail.com>]

You want commands like

bysort patient_id illness_id date of visit : egen meansev = mean(severity)
by patient_id illness_id : gen repeat = _n - 1

as you want to number 0 upwards.


Nick

On Wed, Nov 28, 2012 at 6:28 AM, yannan shen <yannan2010@gmail.com> wrote:

> I am working some panel data of hospital visits and I want to learn
> the severity of various disease.
> The variables I have in the dataset are: patient_id, illness_id,
> date_of_visit, severity
> each observation contains: patient_id, illness_id, date_of_visit, severity.
>
> For each patient (identified by patient_id), I want to know how many
> of times he has visited for the same illness （illness_id ).
> I use the duple command to to label the observation of patients who
> have visited hospital more than once.
>
>> duplicates tag  patient_id illness_id , generate(duple)
>
> However, duple does not give information for any time series
> information. If a patient has 5 visiting records, I want to be able to
> know which is the 0th repeat, 1st repeat, 2nd repeat, 3rd repeat, and
> 4th repeat...I have a vague feeling that I can order those variables
> via date_of_visit but I am still not sure how exactly that can be
> done.
>
> Furthermore, I want to create two new variables: one variable equals
> to the average severity of each disease (disease_id) being treated on
> the same date_of_visit. The other variable equals the highest severity
> of a certain disease being treated on that day. (Ideally, I want to
> create additional variables for each observation)
>
> I have used “bysort” in the past but since now the type is a
> combination of illness_id and date_of_visit， I am a little confused.

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