## Random selection of single measurement of each individuals from a repeated measurement data

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Super Contributor
Posts: 331

# Random selection of single measurement of each individuals from a repeated measurement data

How to randomly select a single measurement of each individuals from a repeated measurement data? My original data is in shape of 'test' and resulting data would look like 'want' except its observations randomly populated.

``````data test;
input ID Age_at_measurement_right	Age_at_measurement_left;
cards;
3232	1.1 1.5
3232	19.3 18.3
3232	33.2 32.1
3236	1.2	1.6
3236	16.2 13.2
3236	23.1 22.1
3266	1.5 1.3
3266	19.3 18.3
3266	33.1 32.3
;

data want;
input ID Age_at_measurement_right	Age_at_measurement_left;
cards;
3232	19.3	18.3
3236	23.1	22.1
3266	1.5	1.3
;``````

Accepted Solutions
Solution
‎11-24-2017 08:31 AM
Super User
Posts: 23,262

## Re: Random selection of single measurement of each individuals from a repeated measurement data

Two common approaches:

1. Add a random variable to each observation.
2. Sort by group and random value.
3. Take the first record for each group.

PROC SURVEYSELECT with N=1 and stratify on GROUP.

All Replies
Solution
‎11-24-2017 08:31 AM
Super User
Posts: 23,262

## Re: Random selection of single measurement of each individuals from a repeated measurement data

Two common approaches:

1. Add a random variable to each observation.
2. Sort by group and random value.
3. Take the first record for each group.

PROC SURVEYSELECT with N=1 and stratify on GROUP.

Super Contributor
Posts: 331

## Re: Random selection of single measurement of each individuals from a repeated measurement data

@Reeza

Hi Reeza, below code worked out. Please let me know if it looks not quite right. Hope I got it.

``````PROC SURVEYSELECT data=test
method=srs n=1
seed=1235 out=test_sample;
strata id;
run;``````
☑ This topic is solved.

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