Count unique values stata

count unique values stata Forget what we have suggested. 05 0. POISSON MODELS FOR COUNT DATA Table 4. College Station, TX: Stata press. 2 kg/m^2. e. Oct 16, 2020 · In Stata, columns are identified by variable names. notes: The Democracy Status Index ranks the countries according to the state of their democracy. dta) Data Files” handout). 96 0 The result is a categorical variable taking values from 1 upward labelling distinct groups. In Stata, most tasks can be performed either by issuing commands within the “Stata command” Identify missing values, which appear as . In this data set, some of the variable names are in the form source_variable, like us2000c_sex and us2000c_age. Collapse allows you to convert your current data set to a much smaller data set of means, medians, maximums, minimums, count or percentiles (your choice of which percentile). tabulate f1. See full list on stata. nunique () team A 4 B 3 Name: points, dtype: int64. in this manual. For rcpoisson, see Right-censored Poisson regression model, Stata Journal 2011, 11(1) pp. Here is an example in a Windows PC (Ado directory may be different among different platforms). Besides reporting the number of unique values, -inspect- also reports: the number of negative, zero, positive, and missing values. Looking at the help of the command, it does not seem possible to store this value. With this two-step j variable (3 values) -> year xij variables: anti90 anti92 anti94 -> anti self90 self92 self94 -> self pov90 pov92 pov94 -> pov ----- Note: The time-invariant variables are repeated across the multiple records for each child. Useful Stata Commands (for Stata versions 13, 14, & 15) Kenneth L. In STATA, this can be done using the command –bysort– and –gen– (i. Tip! Checking for updates is a good idea. Many Stata commands can be executed on a group-by-group basis. As shown in the December, 2015 free webinar “Stata’s Bountiful Help Resources”, you can also explore all the add-on commands via Stata’s “Help” menu. Unique observations are also often interpreted to mean those that occur precisely once in the data. Materials prepared by my former teaching assistant, the late Jamie Przybysz, are also incorporated in these notes. Sum The sum (or total) of the data values. This is an easy way to get see how many observations are in your dataset, but it can also count the number of observations based on a variable which groups observations. Type the following into Stata to see how. 85 1. Deleting missing values is, however not always straightforward. Note that if you want to use probability weights with your data, tabulate can Oct 04, 2018 · Please add [StartTime] and [PhoneNumber] fields into table visual and choose "Count(distinct)" to check if the results are correct. Oct 01, 2010 · The problem with using -tab- to count the unique number of values is its row limits: 12,000 rows (Stata/MP and Stata/SE), 3,000 rows (Stata/IC), or 500 rows (Small Stata). Purely categorical data can come in a range of formats. value_counts () 9 3 7 2 5 1 12 1 4 1 Name: assists, dtype: int64. This new variable contains the number of unique values of the varlist for each level of the by variable. Feb 11, 2019 · Create multiple dummy (indicator) variables in Stata For example, the variable region (where 1 indicates Southeast Asia, 2 indicates Eastern Europe, etc. Also, Stata accepts return scalars (like r (N) with or without Dec 13, 2016 · Tweet. Mar 10, 2016 · Overview. 2 CHAPTER 4. Method: The method is simple. ' and they indicate that it is essential that for panel data, OLS standard errors be corrected for clustering on the Josef Brüderl, Useful Stata Commands, SS 2012 Folie 9 How to repeat yourself without going mad: Loops An extremely helpful technique to do tasks over and over again are loops. N LP UP S+ N LP UP S+ N LP UP S+ 0{4 0. The second step is to associate a specific mapping with a particular variable using the . For visualization, the main difference is that ordinal data suggests a particular display order. The output should be 100. There is no need for r(N_unique) if the number of unique values is less than or equal to 99 as -inspect- reports the actual number. Panel Data. Count(distinct column) is to count the total number of unique values in a column. sort () #display sorted values points array([ 5, 6, 8, 10, 11]) Find and Count Unique Values in a Column. DISTINCT: Stata module to display distinct values of variables. Width of each bin determined automatically by bin size and range of mpg. Abstract: distinct displays the number of distinct values for each variable in a varlist. In this post I will calculate an To calculate such effects in Stata, we need a flexible way of obtaining quantities of interest from the model. ngroup( # ) (default 2) defines the number of groups. Put them in your current directory, in your stata "ado" directory, or in a directory where Stata will know where to look for them. If no frequency variable was specified, this is the number of rows with non-missing values. Most commands in Stata that calculate such summaries select particular sample values or at most average two sample values. Contents 1. by and bysort. Let’s take a look at an example. Common examples of such count data include number of patient hospitalizations (Logan, Radcliffe, & Smith-Whitley, 2002), frequency of adolescent alcohol use (Audrain-McGovern, Rodriguez, Tercyak, Neuner, & Moss, 2006), and number of childhood injuries (Morrongiello, Ondejko, & Littlejohn, 2004 Introduction to Stata version 16 Page 11 of 83 Design Data Collection Data Management Data Summarization Statistical Analysis Reporting Stata will ask you if you would like to check for updates. If we ignore truncation or censoring when analyzing our data, our estimates of population parameters will be inconsistent. That is often sufficient for the purpose intended. Help with bar chart for unique values. Those commands that appear to sidestep it will almost always use it internally. The manuals teach statistics, as well as Stata, and provide statistics references. So, we are going to use the r-class returned results from tab command. To do that we need to have a variable to put it in. count= sets up an initial value for COUNT of 0 (if the first element after sorting is missing) or 1 (if the first element after sorting is nonmissing). describe produces a summary of the dataset, including its storage type, display format, value label and variable label. 41. com For instance: id year x1 111 1999 3 111 2000 5 111 2001 6 123 2000 4 123 2001 2 For the above example, there are 2 unique ids (111 and 123). It "reduces" the data Stata keeps in memory through aggregation. Show activity on this post. Jan 03, 2017 · You can tell Stata how to format the labels by putting a format option inside the blabel option with the format you want. I’ll demonstrate it with an example using the Stata dataset uslifeexp. For example, VARIABLE1 is a generic variable name, and CONDITION is a generic condition you might want to include (like age < 100). Jan 05, 2016 · To add these three commands to your Stata software execute the following code and click on the links to download the commands: findit coefplot findit distinct findit winsor2. 557, the term "unique" has been replaced with "distinct" in the output (but not in parameter names). It also draws a histogram. You can check for duplicate observations in Stata in the following ways: The isid command can detect duplicate observations: . bysort x y: generate count = (_n==1) by x:replace count = sum (count) by y:replace count= count (N) Other method: Jul 19, 2020 · If a variable has more than 9 distinct nonmissing values, Stata's behaviour will depend on the presence of a value label for this variable: If no value labels are present, Stata will display the 10th, 25th, 50th, 75th and the 90th percentile of the variable. Jan 06, 2019 · Using the Stata sort and bysort command will allow us to fix this problem. gen long count = 0 Nov 22, 2016 · Stata dutifully plots two points, but the second one completely covers up the first so that you can only see one. The bysort command has the following syntax: bysort varlist1 (varlist2): stata_cmd. Oct 28, 2010 · In Ways to count the number of unique values in a variable, we have suggested different ways on how to get the number of unique values for a variable. 73 1. The main post-estimation tool Stata has in its arsenal is the margins command. The first Stata lesson here is a reminder of the value of by:. International Economics. Put simply, multi-digit variables without leading zeros “squish” together and you poisgof * Stata 9 and 10 code and output. Stata mess up? In fact, the data have not changed. label define command to create a mapping between numeric values and the words or phrases used to describe those values. COUNT has the value 2 two times, meaning there are two duplicates. Say my dataset was the below. The command is very straight forward. For example the following Stata code will execute the summarize command for each unique value of marital (married, widowed, etc. May 18, 2016 · It would change the values of your existing variables, which is likely a bad outcome. (2010). iquantile offers an alternative, which is perhaps most useful when the number of distinct values is small. (dot) or empty cell inspect varlist (codebook varlist) Identify duplicate observations inspect duplicates (report/drop/tag/list) varlist Identify number of unique values unique varlist (also, codebook for single variable) Browse the dataset browse varlist May 13, 2016 · The Stata result screen will show the result of this action: number of observations deleted. The data are still an integer value of 19274, which is October 8, 2012, when you count days from a zero date of January 1, 1960. In the subsample graphs, a male (blue) point will be covered up by a female (red) point just because the graph for females was the second one specified. These two datasets contain a unique variable id by which they will be mapped. dta format. Cox, 2006. inspect varlist display r(N_unique) Besides reporting the number of unique values, -inspect- also reports: the number of negative, zero, positive, and missing values. ∑ = n i Sum x i 1 = Jun 14, 2021 · bysort country: egen count = total(tag) Since we created a unique identifier by the name of tag, we now use bysort (repeats the command for each group of observations for which the values of the Stata can be used three ways: (1) interactively with menus and dialog boxes; (2) interactively using command syntax; and (3) batch using pre-written programs of code called do-files. Stata Code:. From the output we can see: There are 4 unique ‘points’ values for team Creating a variable equal to the count of unique values across varlist for each observation I have data with a bunch of different date fields that may or may not contain the same information. You can specify many different operators including means, sums, counts, medians, percentiles, standard deviations and more. A count model is a linear model where the dependent variable is a count. With a by it does the same, but also creates a new variable (_Unique by default but can be named in the gen option). " DISTINCT: Stata module to display distinct values of variables ," Statistical Software Components S424201, Boston College Department of Economics, revised 21 Mar 2012. This is generally done using a post-estimation tool. The integer value 19274 is also March 3566 when you count months from a zero date of January 1960. . . Data 3 day ago codebook is a great command in Stata. Stata, Revised Edition, and also the 2014 3 rd edition of Long & Freese. One file containing the X and Y coordinates and another containing list of areas/states etc. ) may need to be converted into twelve indicator variables with values of 1 or 0 that describe whether the region is Southeast Asia or not, Eastern Europe or not, etc. –generate-) or –egen-. For example, the number of times a car breaks down, the number of rats in a litter, the number of times a young student gets out of his seat, etc. It describes data contents but also simply identifies unique values sysuse auto, clear codebook mpg, compact Number of unique values of mpg is 21. You can do the above by using by:, which is one of the most versatile features of Stata. You can use the TYPES statement in PROC SUMMARY to generate a dataset that will make it easy to get those counts using PROC FREQ. 0000 The large value for chi-square in the gof is another indicator that the poisson distribution is not a good choice. Add count of unique / distinct values by group to the original data. groupby (' team ')[' points ']. Option bin(10) specifies number of bins. For example, suppose you want to count the number of observations/rows in auto. "COUNTMATCH: Stata module to count matching values for one variable in another," Statistical Software Components S456784, Boston College Department of Economics, revised 07 Nov 2006. 1f means "format the number such that it fits in no more than nine total spaces (more than enough) with one digit after the decimal point, following the general rules for floating point numbers" but you don't Jun 03, 2008 · Count data with a preponderance of zeros are frequently analyzed by pediatric psychologists. by: is the basic tool for calculations by panels or other groups. Truncation and censoring are two distinct phenomena that cause our samples to be incomplete. Suva Urban Rural Dur. 69 0. The The observations with missing values have to be deleted or the missing values have to be substituted in order for a statistical procedure to produce meaningful results. The distinct count results should be smaller than total row numer of table 'journal'. I want to generate a variable that is the count of unique dates for each row. Coding in Python is a little different than coding in Stata. Cox, 2002. There is a large difference in the number of unique observations (4,999 for the continuous set and 9 for the discrete Poisson set). Everything in Stata is built around this paradigm. Mar 31, 2014 · Stata's "collapse" command: Collapse is a powerful Stata command that lets users aggregate data with "by" constructs and a wide range of statistics. will display a frequency table including percentages and cumulative percentages. This is a handy way to make sure that your ordering involves multiple Also gives the numbers of observations with negative, zero, or positive values; unique values; and missing values. _N gives a count of the total number of observations being worked with. I describe how to generate random numbers and discuss some features added in Stata 14. unique () #sort values smallest to largest points. The dataset is a matrix where each column is a "variable" with a unique name and each row has a number (the special variable _n). May 01, 2020 · The Stata result screen will show the result of this action: number of observations deleted. frac( # ) , which is only allowed with ngroup(2) , specifies that the first group should contain 1 / # of the observations and thus that the second group should contain the remaining observations. The tabulate command. In some datasets, however, missing values may sometimes (partially) be represented by another value in some Nov 06, 2011 · Using _N. When weights are not used, Gini's mean difference is computed for numeric variables. points. For instance, when calculating mean i ncome , a value of - 3 is treated as an income of -3. count if price > 5000 count number of missing/unique values Stata has 6 data types, and data can also be missing: byte true/false Sep 02, 2013 · count - Counts the by a spreadsheet or database program other than Stata. This can distort the understanding you get of the distribution of the two The ranges differ a lot (values are less than zero for the continuous variable). The state of democracy is measured in terms of five criteria, which in turn are SPSS/PASW will allow you to save your data as a Stata file Go to: file -> save as -> Stata (use most recent version available) Then you can just go into Stata and open it; Another option is StatTransfer, a program that converts data from/to many common formats, including SAS, SPSS, Stata, and many more. The variable id has a unique ID number for each child. If results are incorrect, please locate to Query Editor, Trim the fields to remove the invisible characters inside text. One clue to by: being useful here is the structure of a grouping of the variable x into several distinct values. isid x1 x2 x3. In Stata, there are (among others) foreach-loops and forvalues-loops. shp format to stata format, i. Counts are either 0 or a postive whole number, which means we need to use special Dec 02, 2020 · forvalues is used to loop over consecutive values. set obs 100. This is a very flexible tool for producing a variety of quantities of interest from almost all model Categorical data can be. With knowledge of some of the missing values inside the table, we are not surprised to see the first three numbers unmatched. label values command. For a good Stata-specific introduction to survival analysis, seeCleves et al. May 24, 2013 · Sometimes this experience has an effect in future decisions, so we calculate variables that measure the number of times a firm has made an acquisition or has invested in a certain industry or country. ordinal. the unique values of the variable in question, even though such distinct values could all be repeated in the data—and, in particular, 2, 3, and 4 are indeed repeated. Use “adopath” to find out where Stata is looking for ado files. , unique values, duplicates, triplicates, and so on, Counting the number of distinct observations may be required at any point from initial data cleaning or checking to subsequent statistical analysis. Count unique values in Stata. Stata also has several commands for analyzing contingency tables resulting from various forms of observational studies, such as cohort or matched case–control studies. Earlier we looked at how the Stata by command can be used as a prefix for statistical commands (see help by). In particular, Stata 14 includes a new default random-number generator (RNG) called the Mersenne Twister (Matsumoto and Nishimura 1998), a new function that generates random integers, the ability to generate random numbers from an interval, and several new functions that generate random variates To count only observations for which incwage is recorded and greater than $100,000, you have to tell Stata to disregard missing values. For this to work the command must be “byable” (as noted on the online help) and the data must be sorted by the grouping variable(s) (or use bysort instead). describe. Stata by and egen commands. – This document briefly summarizes Stata commands useful in ECON-4570 Econometrics and ECON-6570 Advanced Econometrics. _mm_uniqrows(), and _mm_uniqrows_tag() to count, obtain, or tag unique values/rows without sorting the data Get to know Stata’s collapse command–it’s your new friend. Stata manuals (accessed online and via help) and Stata help itself, are both excellent resources. It will only count sequences of numbers, so the variable that you are calling must include numeric values. do _n_=2 to 131 goes through the remaining elements in the array to see if there is a change in the value. May 19, 2020 · Simulating Data for Count Models. All we need to do is tag the first occurrence of each distinct value, and then count those first occurrences in sequence. display _N. The total number Sep 23, 2011 · You seem to want to count the number of distinct values for a single variable (&COUNTVAR) when crossed with each of a number of other variables (&VARLIST). 90 0. e . Stata orders the data according to varlist1 and varlist2, but the stata_cmd only acts upon the values in varlist1. From the output we can see: The value 9 occurs 3 times. 546 Prob > chi2(312) = 0. Both work in a similar way: They set a user-defined local macro to each Gary Longton & Nicholas J. The following code shows how to find and count the occurrence of unique values in a single column of the DataFrame: Sep 18, 2021 · We can also use the following syntax to find how frequently each unique value occurs in the ‘assists’ column: #count occurrences of every unique value in the 'assists' column df[' assists ']. The duplicates command can list and flag duplicate observations. clear Jul 13, 2016 · The table will usually be easier to read if the variable with the most unique values is listed first. 17 0. Development Economics g2, and g3 that take on values 1 and 0, g1 being 1 when group==1, g2 being 1 when Aug 19, 2012 · Stata counting _n _N. We can use Stata’s margins command to estimate the adjusted predicted BMI for a 50-year old and 25-year old: [D] count Count observations satisfying specified conditions [D] data types Quick reference for data types [D] missing values Quick reference for missing values [D] datetime Date and time values and variables [D] list List values of variables [D] edit Browse or edit data with Data Editor [D] varmanage Manage variable labels, formats, and other A very powerful feature, it instructs Stata to repeat the command for each group of observations defined by distinct values of the variables in the list. Most statistical programs (including SAS, SPSS, and Stata) will automatically remove such cases from any analysis you run (without deleting the cases from the dataset). In Stata, you have one dataset in memory. dta. On the other hand, if you're thinking of the two variables as a dependent variable and an independent variable, the dependent variable is usually listed first so it goes in the rows. If no frequency variable was specified, this is the number of rows with missing values. Stata shows missing values as dots if you view a dataset with the browse command. isid - Checks if data is unique by a listed sorted list of the distinct values of a August 19, 2012. Click OK. 2). The result is not what we may have wanted or expected, but Sep 03, 2020 · If my panel data contain studies appended from 10 different data sets, there are certain variables which shows duplicate values if I calculate incidence or prevalence of an event. One basic tutorial was given in an earlier column (Cox 2002a). The two PROC FREQ steps count all occurrences (i. Oct 15, 2016 · But I fail to create dummy variable in stata 12. xls, SCCS, acts as a quick reference guide (and also summarises some data analysis commands). COUNT has the value 3 one time, meaning there is one triplicate. In addition, percentages are displayed. It assumes that you have set Stata up on your computer (see the “Getting Started with Stata” handout), and that you have read in the set of data that you want to analyze (see the “Reading in Stata Format (. And it doesn’t take long. In some datasets, however, missing values may sometimes (partially) be represented by another value in some Mar 13, 2013 · What this command does is: it will convert the shapefiles that you have downloaded in the . Jun 18, 2020 · The command unique without a by reports the number of unique values for the varlist. In the process it generates two files. I want a bar chart to show the proportion of clinics per clinic type, so in this case the graph should have two bars one displaying 67% of clinics being Count unique values in Stata - Stack Overflow. Describing Your Data. raw data: individual observations; aggregated data: counts for each unique combination of levels. 97 0. You can write out forvalues or use the shortened forval command. The most common are. For the latest version, open it from the course disk space. Stata has thousands of built-in procedures, but you may have tasks that are relatively unique or that you want done in a specific way. 1. The varlist may include both numeric and string variables. August 19, 2012. Alternatively, check out entries on by: indexed in the Stata manual. estat gof Goodness of fit chi-2 = 2234. Frequency tables display the values of a variable, weighted with the number of occurrences of each single value. Missing Count The number of missing data values. We use describe, codebook, list, and count to describe variables to get a sense of our data. Simons – This document is updated continually. nominal, qualitative. Number of unique values of mpg is 21. accompanying Stata commands crib sheet. 50 1. Bookmark this question. Thus, if values of a variable are 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, and 5, then in one sense of “unique”, there are five distinct or unique values—namely, 1, 2, 3, 4, and 5—whereas in another sense there is just one unique value—namely, 1, the only value that occurs precisely once. bysort x y: generate count = (_n==1) by x:replace count = sum (count) by y:replace count= count (N) Other method: egen tag = tag (x y) display the unique values for rep78 Explore Data _N creates a running count of the total observations per group Stata has 6 data types, and data can also be Aug 19, 2012 · Stata counting _n _N. histogram mpg, bin(10) Displays a histogram of mpg with parameters decided by STATA. These phenomena arise in medical sciences, engineering, social sciences, and other research fields. For example, although the variable in question may be measured Creating a variable equal to the count of unique values across varlist for each observation I have data with a bunch of different date fields that may or may not contain the same information. Sep 05, 2013 · The temptation is to do this: egen uniqueid = concat (country village year household) The problems is that household 1 in year 1960 in village 19 in country 11 will have the same id as household 1 in year 1960 in village 119 in country 1 –> 1119601 for both. Variable names are always unique (Stata won't allow you to create two variables with the same name) but they often have multiple parts. Hoping to get some quick help producing a bar chart that considers unique values rather than percent/count of observations. 14 0. Go to Jan 18, 2018 · Adding a value label to a variable in Stata is a two-step process. Quick note: in this document I use all caps to denote things that you’d have to fit in for your own applications. codebook is a great command in Stata. 1: Number of Children Ever Born to Women of Indian Race By Marital Duration, Type of Place of Residence and Educational Level (Each cell shows the mean, variance and sample size) Marr. Instead, use -distinct- (Longton and Cox) to display the number of unique values in a variable or a set of variables (see note). Oct 25, 2021 · The following code shows how to count the number of unique values in the ‘points’ column for each team: #count number of unique values in 'points' column grouped by 'team' column df. COUNT has the value 1 three times (i. We review how far existing commands in official Stata offer solutions to this issue, and we show how to answer questions about distinct observations from first principles by using the by prefix and Microeconometrics using stata (Vol. The take-away here? Examine your outcome variable to determine whether it is discrete or continuous. stata _n N Count / distinct values in groups. Count unique observations in stata keyword after analyzing the system lists the list of keywords related and the list of websites Count unique values in pivot table. , has a Frequency of 3), meaning there are three single values. adopath [1] (UPDATES) "C:\STATA\ado\updates/" Count The number of non-missing data values, n. by id: generate byte posttran = (_n==2) Count distinct values in a variable. Nov 07, 2006 · Nicholas J. The list subcommand lists the duplicate observations: Stata module providing various Mata functions. local counter = 0 local N = _N forvalues i = 1 / `N' { local counter = `counter' + 1} display `counter' Note: this is exactly what's done by the count command. If this check is not done for you Data Integrity Tests for Stata. It describes data contents but also simply identifies unique values. The module is made available under terms of the GPL Feb 11, 2019 · Detect duplicate observations in a data set in Stata. browse make mpg price For different values of var1, how many values of var2 are the same? We will need to loop over the distinct values of var1. 2. In the above example, we count the number of gender categories. Since my dataset has over 6000 observations, what commands should I use to generate a count of unique ids? Jan 24, 2019 · Browse other questions tagged unique stata or ask your own question. Note: This module may be installed from within Stata by typing "ssc install distinct". Jan 18, 2021 · #find unique points values points = df. Jul 03, 2018 · Therefore, the difference in BMI between a 50-year old and 25-year old is on average 1. Forvalues is, arguably, the easiest loop to write. This seems like a tedious process, but let’s see how we can make this exercise simpler using Stata’s margins command. Here, we want to know the number of unique values of the variable year. The first step is to use the . ): Jan 23, 2017 · If the number of unique values is large, it becomes difficult to count them manually. Each time round the loop there will be a count, and then the result will be put into a variable in the right place(s). 95-105. The format %9. One logic behind that terminology is that if you remove all the duplicates from these data, then you are left with four distinct values, each of which occurs once. There are several ways to do this; I recommend the following one (note the exclamation BTI Codebook for Stata | 3 rank_dem_stat Ranking Democracy Status (numeric) unique values: Depending on the respective BTI sample size. bysort x y: generate count = (_n==1) by x:replace count = sum (count) by y:replace count= count (N) Other method: egen tag = tag (x y) In Stata, these negat ive values are treat ed as any other valu e. Launch and run the SAS program, then review the output. You will need to distinguish how you want to count through the number sequence. If you have written a script to perform your task on a given dataset, it is easy to transform that script into something that can be used on all your datasets, on any set of variables, and on any set of Note: As discussed in Cox and Longton (2008), Stata Technical Bulletin 8(4) pp. count unique values stata

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