Stata 15 help for expand

[D] expand -- Duplicate observations


expand [=]exp [if] [in] [, generate(newvar)]


Data > Create or change data > Other variable-transformation commands > Duplicate observations


expand replaces each observation in the dataset with n copies of the observation, where n is equal to the required expression rounded to the nearest integer. If the expression is less than 1 or equal to missing, it is interpreted as if it were 1, and the observation is retained but not duplicated.


generate(newvar) creates new variable newvar containing 0 if the observation originally appeared in the dataset and 1 if the observation is a duplicate. For instance, after an expand, you could revert to the original observations by typing keep if newvar==0.


--------------------------------------------------------------------------- Setup . webuse stackxmpl

List the original data . list

Replace each observation with 2 copies of the observation (original observation is retained and 1 new observation is created) . expand 2

List the results . list

--------------------------------------------------------------------------- Setup . webuse stackxmpl, clear

List the original data . list

Replace each observation with x copies of that observation, where x is the value of b for that observation . expand b

List the results . list


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