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Econ 390

Using STATA Part 3

Do File

New STATA Commands:

1) capture log close

2) log using xxx.log, replace

3) log close

4) do

Note: STATA commands are case sensitive. I capitalized commands and variables (e.g. CLEAR, DVDES25...) in the notes because I want to highlight them. The variable names should be entered (could be either uppercase or lowercase, check the codebook) as in the original data.

1. Create a ‘do’ file.

Up to now, we have been using the ‘interactive’ command mode of STATA. There is an alternative way to run commands using ‘.do’ files.

Do files are sets of commands that are listed in a program. This way of running instructions in STATA is much better because you can easily re-run the same set of commands at a later time and recreate your results.

Everything inside /* */ will be ignored by STATA. So you can put your own comments inside to remind yourself what you are trying to do.

a) Your task is to write a program that does steps 1 to 10 as in Using STATA Part 2.

As an example, here is a sample incomplete program:

/* Sample program */

/* ECON 390 */

clear /* this clears the memory */

capture log close /* this closes any logs that may already be open */

log using "c:\Users\Arts User\Desktop\econ390.log", replace text

/* this opens a log so that screen output can be saved */

/* the ‘replace’ option means that any previous file is replaced */

/* the ‘t’ option means that the log is saved as an ASCII text file */

use "c:\Users\Arts User\Desktop\econ390.dta"

drop if mard==0

keep region rrsp

table region, c(mean rrsp)

log close /* closes the log at the end of the program*/

b) After you have finished and saved the do file as program390.do, you can then run it by using the DO command:

do "c:\Users\Arts User\Desktop\program390.do"

c) After the do file has successfully run in STATA, statistical results generated by such as SUMM and TABLE commands and also regression (REG) results (Part 4) will be saved in the log file.

Now try to open the log file and see what is inside by double clicking the file.

At the end of term, you have to submit your do file and log file with your final paper.

Codebook:

The variables are derived from the 1984 version of the Family Expenditure Survey conducted by Statistics Canada.

Variable

Description

FAMINC

Family income in 1984 dollars.

MARD

Marital status. Takes the value 1 if married or in common-law relationship; 0 otherwise.

AGE

The age of the head of the household.

RRSP

The dollar value of Registered Retirement Savings Plan contributions in 1984, in 1984 dollars.

MTR

Marginal tax rate. The combined (federal/provincial) rate of income tax payable on the last dollar of the head of household’s income.

REGION

Region of residence. Takes the value 1 for Atlantic provinces; 2 for Quebec; 3 for Ontario; 4 for Prairie provinces; 5 for BC.

Some frequently used STATA commands:

Command

Use

cd c:\

Changes directory to c:\

clear

Clears the memory so that a new dataset can be loaded.

dir

Displays contents of current directory

count

Provides a count of the number of observations

desc

Shows variables currently in memory with description

summ

Shows means and standard deviations for all variables - can use ',detail' to get percentiles

reg y x

Runs OLS using y as dependent variable and x as independent variable

gen

Creates new variable

replace

Replaces old value with new value

drop x

Drops variable x

keep x

Drops all variables except for x

drop if x==0

Drops all observations with x=0

keep if x==0

Keeps only those observations with x=0

dprobit

Runs a probit regression, reports marginal probabilities

use data.dta

Brings dataset data.dta into memory

save data.dta

Saves dataset data.dta to disk (add ', replace') to overwrite existing data.dta

table x

Shows a table with the frequency distribution for variable x

table x, c(mean y)

Shows the mean of y for each value of x

compress

Compresses the dataset to take up the minimum amount of memory possible

insheet x y using data.dat, t

Brings variables x and y from ascii file data.dat (tab delimited) into memory

log using econ390.log, t

Creates a log file called econ390.log, text format

log close

Closes any open log file

capture log close

Closes any open log file, but doesn’t crash if there is no open log file

real (x)

Transfers variable x from text to numeric form. e.g. gen numbvar = real(textvar)