<p>The quantity-demanded of a good is the amount of that good the consumer is able and willing to buy. According to the Law of Demand, the quantity-demanded increases when the price of the good falls, while all other factors remain static. Similarly, when the price rises, the quantity-demanded decreases while all other factors remain static. This can be visualised as a movement along the demand curve.</p>
<p>In a promotional sale, the price of a good comes down temporarily. According to the Law of Demand the consumers purchase more of those goods as the price is lower.</p>
<p>Increase in demand is represented by a shift of the demand curve to the right. For the demand curve to shift in any direction, one or more of the following determinants must change:</p>
<ul>
<li>Income</li>
<li>Price of related goods</li>
<li>Taste and preference</li>
<li>Number of buyers in the market</li>
<li>Buyers’ expectations</li>
</ul>
<p>A promotional sale is not a result of any of those factors.</p>
<p>Perhaps the price was reduced to lower the storage costs as the seller was holding too much of stocks. Or the goods were nearing expiry.</p>

CC BY-SA 4.0
2022-03-17T10:32:34.137Z
2022-03-17T10:32:34.137Z
Kaushalya
<p>Your textbook is correct. I believe you are confusing an increase in demand and a shift in the demand curve and conflating the quantity demanded with the demand curve.</p>

<p>The quantity demanded is just how much of the good the consumers want in <strong>one particular case</strong> (e.g. for <strong>one</strong> given price). The demand curve tells you the quantity that would be demanded in all cases (for <strong>any</strong> given price).</p>

<p>Demand can increase without a shift in the curve, as there can be a movement <strong>along</strong> the original curve itself.</p>

<p>A shift in the demand curve, would mean that there is a different (in your case higher) demand at <strong><em>all</em></strong> prices. For example, if the income of the consumers increases, you might expect there to be more demand for the good at <strong>any</strong> given price. Concretely, a shift would mean that previously there were two pairs of shoes being demanded at a price of 50\$ and after the shift there are three pairs of shoes being demanded at a price of 50\$.</p>

<p>The sale on shoes in your example does not cause such an effect. The sale lowers prices, which increases demand (the quantity demanded). It is equivalent to a movement along the demand curve. Before there were e.g. two pairs of shoes being demanded at 50\$ and now the price is e.g. 25\$ so the demanded quantity equals 4 pairs of shoes.</p>

<p>In other words, take a demand curve and use any point on the curve as the situation before the sale. After the sale you have a lower price. Finding the quantity that corresponds to that price <strong>on that same curve</strong> will yield a higher demand, without shifting the curve.</p>

CC BY-SA 4.0
2019-03-09T12:39:43.187Z
2019-03-28T21:02:39.340Z
2019-03-28T21:02:39.340Z
BB King
<blockquote>
  <p>If there is news that shops are having a sale on dress shoes (beginning right now), will it shift the demand curve for this good?</p>
</blockquote>

<p>I initially said yes, as a sale should increase the quantity demanded of dress shoes (resulting in a shift in the demand curve).</p>

<p>However, the answer in my textbook says no. I do not understand.</p>

CC BY-SA 4.0
2019-03-10T02:45:48.277Z
Contrast that with a marketing campaign that makes the shoes more popular at the same price.
fantastic peace and prosperity
<microeconomics>
Effect of Promotional Sales on a Demand Curve
Bell
# Effect of Promotional Sales on a Demand Curve

(Asked by: username_0 on 2019-03-09)

> If there is news that shops are having a sale on dress shoes (beginning right now), will it shift the demand curve for this good?

I initially said yes, as a sale should increase the quantity demanded of dress shoes (resulting in a shift in the demand curve).

However, the answer in my textbook says no. I do not understand.

**Tags:** microeconomics

> **Comments:**
> **username_1**: Contrast that with a marketing campaign that makes the shoes more popular at the same price.  

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## 2 answers

### Answer by username_3 on 2019-03-09. Score: 3 | Accepted answer

Your textbook is correct. I believe you are confusing an increase in demand and a shift in the demand curve and conflating the quantity demanded with the demand curve.

The quantity demanded is just how much of the good the consumers want in **one particular case** (e.g. for **one** given price). The demand curve tells you the quantity that would be demanded in all cases (for **any** given price).

Demand can increase without a shift in the curve, as there can be a movement **along** the original curve itself.

A shift in the demand curve, would mean that there is a different (in your case higher) demand at ***all*** prices. For example, if the income of the consumers increases, you might expect there to be more demand for the good at **any** given price. Concretely, a shift would mean that previously there were two pairs of shoes being demanded at a price of 50\$ and after the shift there are three pairs of shoes being demanded at a price of 50\$.

The sale on shoes in your example does not cause such an effect. The sale lowers prices, which increases demand (the quantity demanded). It is equivalent to a movement along the demand curve. Before there were e.g. two pairs of shoes being demanded at 50\$ and now the price is e.g. 25\$ so the demanded quantity equals 4 pairs of shoes.

In other words, take a demand curve and use any point on the curve as the situation before the sale. After the sale you have a lower price. Finding the quantity that corresponds to that price **on that same curve** will yield a higher demand, without shifting the curve.


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### Answer by username_2 on 2022-03-17. Score: 1

The quantity-demanded of a good is the amount of that good the consumer is able and willing to buy. According to the Law of Demand, the quantity-demanded increases when the price of the good falls, while all other factors remain static. Similarly, when the price rises, the quantity-demanded decreases while all other factors remain static. This can be visualised as a movement along the demand curve.

In a promotional sale, the price of a good comes down temporarily. According to the Law of Demand the consumers purchase more of those goods as the price is lower.

Increase in demand is represented by a shift of the demand curve to the right. For the demand curve to shift in any direction, one or more of the following determinants must change:

* Income
* Price of related goods
* Taste and preference
* Number of buyers in the market
* Buyers’ expectations

A promotional sale is not a result of any of those factors.

Perhaps the price was reduced to lower the storage costs as the seller was holding too much of stocks. Or the goods were nearing expiry.


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