How do you check for duplicates in Stata?

You can check for duplicate observations in Stata in the following ways:

The isid command can detect duplicate observations: .
The duplicates command can list and flag duplicate observations.
The tag subcommand and the generate() option flag duplicate observations by assigning 1 to duplicacy in the variable duple : .

What does duplicates drop do in Stata?

duplicates drop drops all but the first occurrence of each group of duplicated observations. The word drop may not be abbreviated. Any observations that do not satisfy specified if and/or in conditions are ignored when you use report, examples, list, or drop.

What is quietly in Stata?

Quietly The command quietly simply tells Stata to not show the execution of the com- mand on the Result window. This is particularly useful when you want to create a lot of variables from a loop, or from a tabulate procedure (to get dummy variables).

What is Joinby Stata?

joinby joins, within groups formed by varlist, observations of the dataset in memory with filename, a Stata-format dataset. By join we mean to form all pairwise combinations. If varlist is not specified, joinby takes as varlist the set of variables common to the dataset in memory and in filename.

What does by () do in Stata?

bysort varlist1[(varlist2)] [ , rc0 ] : stata cmd. Description. Most Stata commands allow the by prefix, which repeats the command for each group of observations for which the values of the variables in varlist are the same. by without the sort option requires that the data be sorted by varlist; see [D] sort.

Why use quietly regress Stata?

Stata’s quietly command allows commands to be run without outputting to the results window. This is useful if you only require the returned results. NOTE: quietly is often used in programs, and is useful when you are using Stata interactively and want to temporarily suppress the terminal output.

What are globals in Stata?

In Stata, a global macro is something that is stored in memory and can be used anytime during a Stata session by reference to its name (a local macro differs basically inasmuch it can be used only within a circumscribed piece of a program or a do-file).

What are duplicates in Stata?

In Stata terms, duplicates are observations with identical values, either on all variables if no varlist is speciﬁed, or on a speciﬁed varlist; that is, 2 or more observations that are identical on all speciﬁed variables form a group of duplicates.

What does _n mean in a Stata report?

(Stata interprets _N to mean the total number of observations in the by-group and _n to be the observation number within the by-group.) Having created the new variable dup, you could then to see a report of the duplicate count. To base the duplicate count solely on name, type

What is duplicates tag in SQL Server?

A subcommand that is occasionally useful is duplicates tag, which generates a new variable containing the number of duplicates for each observation. Thus unique observations are tagged with value 0, and all duplicate observations are tagged with values greater than 0.

How do I remove duplicate observations from a list?

To base the duplicate count solely on name, type To base the duplicate count on name, age, sex, and address, type Picking up where case 1 left off, if you want to drop all duplicate observations but keep the first occurrence, type To drop all duplicate observations, including the first occurrence, type