Re: st: Identifying Experiment subjects that belong in both the Placebo and Experiment Groups

[Maarten Buis <maartenlbuis@gmail.com>]

On Mon, Oct 22, 2012 at 12:30 PM, Beatrice Benavidez wrote:
> Thank you for your reply. But what if my dataset is structured like below:
>
> Date          ID          Received
> 18/1           3            Treatment
> 19/1           3            Placebo
> 20/1           3            Treatment
> 18/1           4            Placebo
> 18/1           4            Treatment
> 18/1           4            Placebo
> 18/1           4            Treatment
>
> The particular ID's first and last observation may be the same but the
> in-betweens are different.
>
> The line "bysort ID (Received) : gen bad = Received[1] !=
> Received[_N]" may not work as [1] and [_N] only deals with first and
> last respectively.

What is first and what is last depends on how you sort your dataset.
You seem to think that the dataset is sorted by ID and Date, but the
line -bysort ID (Received) : ... sorts by ID and Recieved, thus
solving your problem.

-- Maarten

---------------------------------
Maarten L. Buis
WZB
Reichpietschufer 50
10785 Berlin
Germany

http://www.maartenbuis.nl
---------------------------------
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