Change in Demand vs. Change in Quantity Demanded

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♪ [music] ♪
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- [Narrator] Economists
use similar terms
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for two things
which are quite different:
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a change in the quantity demanded
versus a change in demand.
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It can be a little confusing,
so let's review.
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A change in quantity demanded
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refers to a movement
along a fixed demand curve --
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that's caused by a change in price.
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A change in demand refers
to a shift in the demand curve --
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that's caused
by one of the shifters:
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income, preferences,
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changes in the price
of related goods and so on.
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Let's illustrate the difference
with a refreshing example.
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We'll use soda.
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- [Woman 1] Um, don't you mean pop?
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- [Man] That's a coke, y'all!
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- [Woman 2] Actually, soft drink
is the most accurate term, so...
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- [Narrator] Fine, we'll just use
sugary, fizzy drinks, okay?
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First, let's recall a change
in the quantity demanded.
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Suppose the price
on sugary, fizzy drinks
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goes from \$3 to \$4.
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What happens?
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Well, the quantity demanded
decreases from 200 to 150.
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There's a decrease
in the quantity demanded
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marked by movement
along the demand curve.
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But there's no change
in the existing demand curve.
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Now, let's look at
a change in the demand,
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in this case, a decrease in demand
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of [sighs] sugary, fizzy drinks,
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caused by a viral
marketing campaign
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for naturally sweetened
sparkling water.
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People just aren't as excited
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The decrease in demand
shifts the entire demand curve
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down and to the left
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to a lower quantity at every price.
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In the first case, on the left,
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we have a decrease
in the quantity demanded --
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that is a movement
along a fixed demand curve.
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In the case on the right,
we have a decrease in demand.
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The entire demand curve
shifts down and to the left.
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An easy way to remember this
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is that our graph tracks changes
in price and quantity.
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If a change occurs in a variable
other than price or quantity --
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that is, something
not measured on either axis --
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that will represent a shift
in the demand curve.
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Prices on the vertical, or y-axis,
so a change in price alone,
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will cause movement
along the curve.
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A change in income,
population, tastes, etc. --
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none of these are measured
on either axis,
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and thus, we'll see a shift
in the entire demand curve.
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So there you have it.
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Similar terminology
can be confusing,
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but if you follow the curves,
you won't have to worry.
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If you're a teacher,
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you should check out
our Supply and Demand unit plan
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that incorporates this video.
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If you're a learner,
make sure this video sticks
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quick practice questions.
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for more microeconomics,
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click for the next video.
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♪ [music] ♪
Title:
Change in Demand vs. Change in Quantity Demanded
Description:

What is the difference between a change in quantity demanded and a change in demand?

This video is perfect for economics students seeking a simple and clear explanation.

A *change in demand* refers to a shift in the demand curve, which is caused by a number of factors such as income, population, etc. A *change in quantity demanded* refers to a movement along a fixed demand curve, which is caused by a change in price.

Master this concept by watching the video and then taking the practice questions.

***TEACHER RESOURCES***
Supply and Demand 5-day HS unit plan: https://mru.io/finding-equilibrium-8d0d3

Assessment questions: https://mru.io/principles-29121

EconInbox, a free weekly email of class-ready news articles, videos, and more: https://mru.io/econinbox-0818b

More high school teacher resources: https://mru.io/high-school-c89b8

More professor resources: https://mru.io/university-teaching-d5289

***CONTINUE LEARNING***
Next video—A Deeper Look at the Supply Curve: https://mru.io/look-supply-d33ae

Practice questions: https://mru.io/go0

Full Microeconomics course: https://mru.io/qez

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Video Language:
English
Team:
Marginal Revolution University
Project:
Micro
Duration:
03:19
 Kirstin Cosper edited English subtitles for Change in Demand vs. Change in Quantity Demanded Kirstin Cosper edited English subtitles for Change in Demand vs. Change in Quantity Demanded Theresa Ranft edited English subtitles for Change in Demand vs. Change in Quantity Demanded Theresa Ranft edited English subtitles for Change in Demand vs. Change in Quantity Demanded Theresa Ranft edited English subtitles for Change in Demand vs. Change in Quantity Demanded Theresa Ranft edited English subtitles for Change in Demand vs. Change in Quantity Demanded Theresa Ranft edited English subtitles for Change in Demand vs. Change in Quantity Demanded

English subtitles

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Kirstin Cosper
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Theresa Ranft
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