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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
    about sugary, fizzy drinks anymore.
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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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    and leads, as we know,
    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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    by answering a few
    quick practice questions.
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    Or if you're ready
    for more microeconomics,
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    click for the next video.
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    ♪ [music] ♪
Titolo:
Change in Demand vs. Change in Quantity Demanded
Descrizione:

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
Progetto:
Micro
Duration:
03:19

English subtitles

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