Return to Video

Change in Demand vs. Change in Quantity Demanded

  • 0:00 - 0:03
    ♪ [music] ♪
  • 0:14 - 0:16
    - [Narrator] Economists
    use similar terms
  • 0:16 - 0:18
    for two things
    which are quite different:
  • 0:18 - 0:23
    a change in the quantity demanded
    versus a change in demand.
  • 0:23 - 0:25
    It can be a little confusing,
    so let's review.
  • 0:25 - 0:27
    A change in quantity demanded
  • 0:27 - 0:31
    refers to a movement
    along a fixed demand curve --
  • 0:31 - 0:33
    that's caused by a change in price.
  • 0:34 - 0:38
    Change in demand refers to
    a shift in the demand curve --
  • 0:38 - 0:41
    that's caused by one
    of the shifter's income,
  • 0:41 - 0:46
    preferences, changes
    in the price of goods and so on.
  • 0:46 - 0:49
    Let's illustrate the difference
    with a refreshing example.
  • 0:49 - 0:52
    We'll use soda.
  • 0:52 - 0:53
    Um, don't you mean pop?
  • 0:53 - 0:55
    That's coke, y'all!
  • 0:55 - 0:59
    Actually, soft drink
    is the most accurate term, so...
  • 0:59 - 1:01
    - [Narrator] Fine, we'll just use
    sugary, fizzy drink, okay?
  • 1:01 - 1:05
    First, let's recall a change
    in the quantity demanded.
  • 1:05 - 1:08
    Suppose the price
    on sugary, fizzy drinks
  • 1:08 - 1:10
    goes from $3 to $4.
  • 1:10 - 1:11
    What happens?
  • 1:11 - 1:17
    Well, the quantity demanded
    decreases from 200 to 250.
  • 1:17 - 1:19
    There's a decrease
    in the quantity demanded
  • 1:19 - 1:22
    marked by movement
    along the demand curve.
  • 1:22 - 1:25
    But there's no change
    in the existing demand curve.
  • 1:26 - 1:29
    Now, let's look at
    a change in demand,
  • 1:29 - 1:32
    in this case, decrease
    in the demand of
  • 1:33 - 1:35
    (sighs) sugary, fizzy drinks
  • 1:35 - 1:37
    caused by a viral
    marketing campaign
  • 1:37 - 1:40
    for naturally sweetened,
    sparkling water.
  • 1:40 - 1:44
    People just aren't as excited
    about sugary, fizzy drink anymore.
  • 1:44 - 1:48
    The decrease in demand
    shifts the entire demand curve
  • 1:48 - 1:49
    down into the left
  • 1:49 - 1:54
    and leaves, as we know,
    to a lower quantity at every price.
  • 2:01 - 2:03
    In the first case, on the left,
  • 2:03 - 2:05
    we have a decrease
    in the quantity demanded --
  • 2:05 - 2:09
    that is a movement
    along a fixed demand curve.
  • 2:09 - 2:10
    In the case on the right,
    we have a decrease in demand,
  • 2:10 - 2:15
    the entire demand curve
    shifts down into the left.
  • 2:15 - 2:17
    An easy way to remember this
  • 2:17 - 2:20
    is that our graph track changes
    in price and quantity.
  • 2:20 - 2:24
    If a change occurs in a variable
    other than price or quantity --
  • 2:24 - 2:27
    that is, something
    not measured on either axis --
  • 2:27 - 2:31
    that will represent a shift
    in the demand curve.
  • 2:31 - 2:35
    Prices on the vertical or y-axis,
    so change in price alone,
  • 2:35 - 2:38
    will cause movement
    along the curve.
  • 2:38 - 2:41
    A change in income,
    population, tastes, etc. --
  • 2:41 - 2:43
    none of these are measured
    on either axis
  • 2:43 - 2:48
    and thus, we'll see a shift
    in the entire demand curve.
  • 2:48 - 2:49
    So there you have it.
  • 2:49 - 2:51
    Similar terminology
    can be confusing,
  • 2:51 - 2:54
    but if you follow the curves,
    you won't have to worry.
  • 2:58 - 2:59
    If you're a teacher,
  • 2:59 - 3:01
    you should check out
    our supply in demand [ ]
  • 3:01 - 3:03
    that incorporates this video.
  • 3:03 - 3:05
    If you're a learner,
    make sure this video sticks
  • 3:05 - 3:08
    by answering a few
    quick practice questions.
  • 3:08 - 3:10
    Or if you're ready
    for more microeconomics,
  • 3:10 - 3:12
    click for the next video.
  • 3:13 - 3:15
    ♪ [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

more » « less
Video Language:
English
Team:
Marginal Revolution University
Project:
Micro
Duration:
03:19

English subtitles

Revisions Compare revisions