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Re: st: Deleteing all observations for individuals with anomalousdata


From   celdjt@umich.edu
To   statalist@hsphsun2.harvard.edu, Antoine Terracol <Antoine.Terracol@univ-paris1.fr>
Subject   Re: st: Deleteing all observations for individuals with anomalousdata
Date   Mon, 08 Aug 2005 12:42:01 -0400

On the other hand, might be an idea to think carefully about your approach to
handling missing data and consider whether there are preferable alternatives.
Perhaps a brief look at Paul Allison little book "Missing Data" as well as some
of the multiple imputation programs available to run under Stata.

Quoting Antoine Terracol <Antoine.Terracol@univ-paris1.fr>:


le 08/08/2005 17:51, Murray Lowe a ecrit :
Hi,

I am new to Statalist, hope someone can help me!

I am working with a large dataset and have discovered that some of the data
are missing values or have erroneous values. The data is panel data with
observations per individual over a 5 year period. For example:

ID	Year	Cost

1	1	100
1	2	200
1	3	500
1	4	150
1	5	x
2	1	100
2	2	200
2	3	500
2	4	600
2	5	100

The problem is this: If an individual has a missing / erroneous value for a
particular year, I want to exclude ALL of their observations from the
dataset. In the example patient 1 would be removed from the dataset
entirely. How can this be done through an automated-type process?
Essentially I need a code / method that looks for the anomalous data;
identifies the patient and then removes all of their observations from the
dataset.

Hope you can help,

Murray Lowe

Hello,

I would try something like :

generate tag=(cost==.)
egen toberemoved=sum(tag), by(ID)
drop if toberemoved>0
drop tag toberemoved


You will need to replace the "cost==." in the fisrt line by a more general way to tag your erroneous values (such as "cost==. | cost>9999")

Best,
Antoine

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