- [Narrator] On his quest to master econometrics,
Grasshopper Kamal has made great progress
stretching his capabilities and outsmarting his foes.
Alas, today he's despondent.
For one challenge remains unmet.
Kamal cannot yet decode the scriptures of academic research,
journals like "The American Economic Review"
and "Econometrica."
These seemed to him to be inscribed in an obscure foreign tongue.
- [Kamal] Ugh, what the... ?
- [Narrator] These volumes are opaque to novice, Kamal,
but can be deciphered with study.
Let us learn to read them together.
Let's dive into the West Point study,
published in the "Economics of Education Review."
This paper reports on a randomized evaluation
of student electronics use in Economics 101 classrooms.
First, a quick review of the research design.
- Okay.
- [Josh] 'Metrics masters teaching at West Point,
the military college that trains American Army officers
designed a randomized trial to answer this question.
These masters randomly assigned West Point cadets
into Economics classes operating under different rules.
Unlike most American colleges,
the West Point default is no electronics.
For purposes of this experiment, some students were left
in such traditional technology-free classes,
no lap tops, no tablets and no phones!
[voice echoes]
This is the control group, or baseline case.
Another group was allowed to use electronics.
This is the treatment group, subject to a changed environment.
The treatment in this case is the unrestricted use
of laptops or tablets in class.
Every causal question has a clear outcome,
the variables we hope to influence defined in advance of the study.
The outcomes in the West Point electronics study
are final exam scores.
The study seeks to answer the following question,
what is the causal effect of classroom electronics on learning
as measured by exam scores?
- Economics journal articles usually begin with a table
of descriptive statistics, giving key facts
about the study sample.
- Oh my gosh, I remember this table, so confusing!
Columns 1 to 3 report mean, or average, characteristics.
These give a sense of who we're studying.
Let's start with column 1 which describes covariates
in a control group.
Covariates are characteristics of the control and treatment groups
measured before the experiment begins.
For example, we see the control group has an average age a bit over 20.
Many of these covariates are dummy variables.
A dummy variable can only have two values, a zero or a one.