Stata tutorial

From our last article, you should feel comfortable with the idea of editing and saving data sets in Stata. In this article, we’ll explain how to create new variables in Stata using replace, generate, egen, and clonevar.

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Stata makes it a breeze to edit or clean your data. If you’re unfamiliar with using data sets in Stata, check out these blog posts to get a good grasp on importing and browsing data in Stata.

For this tutorial we will be using Stata’s “auto” data set. If you haven’t loaded it in yet, type

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Once you’ve imported your data into Stata the next step is usually examining it.

Before you work on building a model or running any tests, you need to understand your data. Ask yourself these questions:

• Is every variable marked as the appropriate type?
• Are missing observations coded consistently and marked as missing?
• Do I want to exclude any variables or data points?

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If you’ve tried coding in Stata, you may have found it strange. The syntax rules are straightforward, but different from what I’d expect.

I had experience coding in Java and R before I ever used Stata. Because of this, I expected commands to be followed by parentheses, and for this to make it easy to read the code’s structure.

Stata does not work this way.

An Example of how Stata Code Works

To see the way Stata handles a linear regression, go to the command line and type

h reg or help regress

You will see a help page pop up, with this Syntax line near the top.

(If you need a refresher on getting help in Stata, watch this video by Jeff Meyer.)

This is typical of how Stata code looks. (more…)

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From our first Getting Started with Stata posts, you should be comfortable navigating the windows and menus of Stata. We can now get into  programming in Stata with a do-file.

Why Do-Files?

A do-file is a Stata file that provides a list of commands to run. You can run an entire do-file at once, or you can highlight and run particular lines from the file.

If you set up your do-file correctly, you can just click “run” after opening it. The do-file will set you to the correct directory, open your dataset, do all analyses, and save any graphs or results you want saved.

I’ll start off by saying this: Any analysis you want to run in Stata can be run without a do-file, just using menus and individual commands in the command window. But you still should make a do-file for the following reason:

Reproducibility (more…)

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In part 3 of this series, we explored the Stata graphics menu. In this post, let’s look at the Stata Statistics menu.

Statistics Menu

Let’s use the Statistics menu to see if price varies by car origin (foreign).

We are testing whether a continuous variable has a different mean for the two categories of a categorical variable. So we should do a 2-sample t-test. (more…)

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