RE: st: differentiating between groups of records with same date

[Tim Evans <Tim.Evans@wmciu.nhs.uk>]

Hi Nick,

I've been taking a look at the reference you pointed me to, and been experimenting, to see how I would count for each patient, the number of different procedures that took place on the same date.

Again I have 

patient_no      cancer_no       diag_date       surgery_date 	proc_type
 9512834         0484360 	 21may1994       21may1994	H1
 9512834         0484358 	21may1994       21may1994	H2
 9512834         0483234 	26apr2000       21may2000	H1
 9512834         0483233 	26apr2000
 0000012	     0000012	      21Jan1999        21Jan1999	H3
 0000012	     0000013	      21Jan1999        21Jan1999	H3     
 0000012	     0000014	      21Jan1999        21Jan1999	H3	

So I want to say that patient 9512834 had 2 different proc_types on 21may1994 and that patient 0000012 had one operation.

Best wishes

Tim


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Tim Evans
Sent: 31 July 2012 10:53
To: 'statalist@hsphsun2.harvard.edu'
Subject: RE: st: differentiating between groups of records with same date

Nick,

Thanks for this, a handy piece of code/functionality.

Best wishes
Tim


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox
Sent: 30 July 2012 17:50
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: differentiating between groups of records with same date

bysort patient_no diag_date: gen freq = _N

See also

SJ-2-1  pr0004  . . . . . . . . . . Speaking Stata:  How to move step by: step
        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  N. J. Cox
        Q1/02   SJ 2(1):86--102                                  (no commands)
        explains the use of the by varlist : construct to tackle
        a variety of problems with group structure, ranging from
        simple calculations for each of several groups to more
        advanced manipulations that use the built-in _n and _N


Nick

On Mon, Jul 30, 2012 at 10:20 AM, Tim Evans <Tim.Evans@wmciu.nhs.uk> wrote:
> Hi all,
>
> I have a group of patients who are in a dataset of cancers. Each patient may have more than one cancer diagnosed, and so may be present in my dataset a number of times. Each patient has a unique patient identifier, and each cancer has a unique cancer identifier. Each row of data is cancer specific, but does contain the patient identifier. It is possible that a patient has 2 cancers diagnosed on the same day in my dataset. What I would like to do is generate a flag next to each record to show against each cancer the number of cancers diagnosed on the same day.
>
> My data are like this:
>
> patient_no              cancer_no       diag_date       surgery_date
> 9512834         0484360 21may1994       21may1994
> 9512834         0484358 21may1994       21may1994
> 9512834         0483234 26apr2000       21may2000
> 9512834         0483233 26apr2000
> 0000057         0000057 19jul2009       19jul2009
> 0000060         0000060 02nov2009       24nov2009
> 0000074         0000074 21sep2009       22nov2009
>
>
> For example, patient 9512834 had 2 cancers diagnosed on 21may1994 and so for cancer_no 0484360 and 0484358, I would like to generate a new variable with the value 2 against each record. Similiarly patient 0000057 has only one cancer diagnosed, and so the new variable would contain 1.
>
>

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