The
typical
first
-
year
student
walks
into
his
first
class
with
very
little
idea
of
what
is
.
He
might
have
heard
something
like
,
"
economics
is
the
study
of
money
"
,
or
"
economics
is
another
word
for
accounting
"
,
or
"
economics
is
hard
,
don't
take
that
class
"
,
but
none
of
those
are
true
.
"
Economics
is
the
study
of
the
use
of
scarce
resources
that
have
alternative
uses
.
"
That's
the
classic
definition
of
economics
.
Basically
,
there
are
people
,
and
people
need
resources
to
fulfil
their
desires
.
These
cannot
be
infinite
,
but
the
desires
can
be
,
so
people
need
to
make
choices
about
how
to
use
their
scarce
resources
.
Economists
study
these
choices
.
All
economic
questions
fall
into
one
of
two
categories
:
positive
and
normative
.
economics
describes
"
what
is
"
and
normative
economics
argues
for
what
ought
to
be
,
so
a
question
like
,
"
why
do
people
use
money
?
"
is
a
positive
question
and
"
should
people
use
money
?
"
is
a
normative
question
.
A
general
rule
of
thumb
is
that
if
your
economic
model
has
no
value
judgements
,
it's
positive
economics
,
and
if
it
does
have
value
it's
economics
,
since
to
tell
someone
what
he
ought
to
do
,
you
first
have
to
judge
what
is
best
for
him
.
Economics
is
also
divided
into
microeconomics
and
macroeconomics
.
studies
the
behaviour
of
individual
agents
and
markets
,
while
macroeconomics
studies
the
behaviour
of
the
entire
economy
.
Economists
also
have
their
own
branch
of
called
"
econometrics
"
that's
specialized
to
analyzing
economic
data
.
Since
economic
data
usually
comes
from
the
real
world
,
and
not
from
controlled
experiments
,
econometrics
faces
mathematical
challenges
that
other
fields
might
not
.
The
tools
economists
have
developed
to
study
human
have
broad
uses
outside
of
what
we
would
traditionally
consider
economics
.
Economists
study
not
only
,
but
things
like
crime
,
war
,
the
family
,
religion
,
culture
,
politics
,
law
,
and
even
genetics
.
That's
why
it's
not
unusual
to
see
papers
by
psychologists
,
sociologists
,
criminologists
,
political
scientists
,
anthropologists
,
biologists
,
neuroscientists
,
or
legal
scholars
being
co
-
authored
by
economists
.