Differentiate between perfectly elastic and also inelasticUnderstand the difference in between elasticity on a single curve and also relative elasticityExplain what variables affect elasticity of supply and also demand
(Credit: University of Victoria Students’ Society)

Textbook or Burger?

In Topics 4.1 and 4.2, we looked at elasticity on a single demand also curve and also examined just how responsive consumer are to price changes at miscellaneous levels of production. But what about responsiveness across firms? Across industries? We recognize that in specific industries, such as the textbook industry, consumers are less responsive to change than others. How is the amount demanded for textbooks affected by a boost in price? If the textbook for a course climbed from $100 to $150, what would you do? Many students will certainly buy the book anyway, considering that it is a required course product. Publishers are significantly utilizing different techniques to encertain the market stays inelastic or unresponsive to price adjust, such as bundling the textbook through mandatory course access codes. Compare this case with the price of a burger. If the price of a burger rises from $8 to $12, you may purchase lunch from a different restaurant or begin packing lunch from residence. The market for textbooks and also burgers are incredibly various. In this area, we will explore the relative elasticity of various markets.

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 Perfectly Elastic and Perfectly Inelastic

To start the conversation around loved one elasticity, it helps to first look at the extremes.

Perfectly Elastic

Imagine a product where if the price enhanced, even slightly, you wouldn’t buy any type of it anyeven more. Sound familiar? That’s bereason we presented this idea in Topic 3, as one of the assumptions of a perfectly competitive market. One of the examples we used was the same warm dog stands, side by side, where the only difference was price. If top quality is the exact same, the rational customer will constantly purchase the warm dog that is a reduced price. From the perspective of the stand, they understand that if they increase price even slightly, they will certainly sell 0 units. This suggests that ED = ∞.

Using point-slope at any type of allude in Figure 4.3a, we deserve to confirm this.

fracDelta QDelta Pcdot fracPQ=?

We know that fracDelta QDelta P is equal to the inverse of the slope. In the demand also curve in Figure 4.3a, once the ΔP>0 then ΔQ is equal to ∞. This indicates that fracDelta QDelta P = ∞. 

Figure 4.3a

Perfectly Inelastic

At the other finish of the spectrum, take into consideration a industry wbelow the firm deserve to continue to rise prices through no change in quantity. If you were poisoned and also had actually to buy the antidote, would you be responsive to price change? Probably not. This is an instance of a situation wbelow demand is nearly perfectly inelastic. If you boost the price, quantity demanded does not readjust. This suggests that ED = 0.

We can confirm this by making use of point-slope at any point in Figure 4.4a.

In the demand also curve in Figure 4.3a, once the ΔP>0 then ΔQ is equal to 0. This suggests that fracDelta QDelta P = 0. 

Figure 4.3b

 Relative Elasticity

The ideas of perfectly elastic and also perfectly inelastic lead us into a discussion of family member elasticity. In 4.1 and 4.2, we examined a single demand also curve, and also looked at the numerical worth of elasticity along that demand curve. However, elasticity deserve to additionally be valuable once comparing demand also curves. Even though each demand curve has an inelastic, elastic, and unit elastic section, the compariboy of the curves have the right to display which markets are fairly even more responsive to price changes. This is a critical principle to understand also for when we look at the results of a policy adjust.

Figure 4.3c

Figure 4.3c illustprices two curves. One is reasonably more inelastic and the various other is reasonably even more elastic. The ideal method to identify which is even more elastic or inelastic is to compare each curve to the extremes. The curve more resemblant of perfect elasticity is fairly even more elastic, the curve even more resemblant or perfect inelasticity is relatively even more inelastic. Keep in mind this is various than saying one is elastic and also the other inelastic! To emphadimension this allude, review the section “Bears and Elasticity.”

Bears and Elasticity

(Credit: Wapster/ Flickr/ CC BY 2.0)

A bear jumps out of a bush and starts chasing 2 hikers. They both start running for their lives, but then among them stops to put on his running shoes.

His frifinish says, “What are you doing? You can’t outrun a bear!”

His frifinish replies, “I don’t need to outrun the bear; I just have to outrun you!”

If both friends are trying to acquire ameans from the bear and you learn that among them is fast, does this information tell you that gets eaten? No! It just matters which one is faster, or rapid loved one to the various other. Relative elasticity is the same. In truth, we cannot pass judgement if one is elastic or inelastic unless we are referencing to another.

The concept of relative elasticity is not based on the calculations in 4.1 and also 4.2, as each demand also curve has actually an inelastic, elastic and unit elastic region. Demand also curves take the form of anything between perfectly elastic and also perfectly inelastic, and also you can just judge loved one elasticity in referral to various other curves.

What About Supply

The same ideas and principles have the right to be applied to supply. Tright here is fairly significant variation across different industries, through some reasonably even more elastic than others.

Factors That Influence Relative Elasticity

So what reasons this distinction in family member elasticity? For the many component, exterior determinants which influence responsiveness.


Availability of substitutes

The availability of substitutes is a strong aspect in determining the elasticity of a great. If tright here are many type of close substitutes, then it is sensibly simple for consumers to discover an ideal alternate to an excellent if prices increase.

Necessity of a good

In enhancement, the extent to which a great is a necessity or a high-end considerably impacts its elasticity. Essentials, such as soap, flour, sugar, and so on are mainly purchased in the exact same quantity regardless of price. On the other hand, consumers are exceptionally price conscious once it involves high-end goods (such as comforts, jewelry, and so on.).


The necessity of an excellent depends fairly heavily on the customer’s revenue. Someone with low revenue could be more price conscious (elastic) as soon as purchasing a brand-new sofa compared to someone via higher revenue. Normally the bigger percent of your revenue a great takes up, the even more sensitive you will be to price changes.


What causes supply to be even more or less elastic?

Availability of resources

If a company’s manufacturing is dependent on scarce resources, the firm is less responsive to changes in price. Even if prices are high and also the firm desires to increase production, it wont be able to without the appropriate inputs.

Technological development

Innovation often tends to lead to even more efficient manufacturing. If a firm benefits from optimal notch production technology, it will be even more able to respond to an increase in price through a rise in production.

Barriers to entry

If tright here are few barriers to enattempt in an market, a boost in price deserve to reason a large rise in manufacturing as brand-new firms quickly enter the industry.

Time: The Ever-Constraining Factor

Both the elasticity of supply and demand are influenced by time. For the customer, just how a lot time they have to make a usage decision. For the producer, exactly how a lot time it has to develop the great and construct inventory. Regardmuch less of whether we are talking around supply or demand also, a rise in time always rises the elasticity of an excellent by boosting the capacity to act and make informed decisions.


Whereas tough labels such as elastic, unit elastic, and also inelastic can be used to define specific sections of supply and also demand curves (based on a calculated value), as soon as comparing two curves every little thing is family member. Using the knowledge of perfect elasticity and also perfect inelasticity, we have the right to compare two curves on the basis of elasticity to recognize how responsive the basic customer team, industry, and so on is to price alters. A flast curve is fairly even more elastic than a steeper curve. Availability of substitutes, a items requirement, and a consumers revenue all affect the loved one elasticity of demand also. The availability of sources, technological creation, and the obstacles to entry all influence the relative elasticity of supply. Time affects elasticity of either curve.

Now that we have actually the tools of supply, demand also and also elasticity, we will usage them to understand just how government policy affects the industry.


Perfectly Elasticthe extremely elastic case of demand or supply wbelow quantity transforms by an limitless amount in response to any kind of adjust in price; horizontal in appearancePerfectly Inelasticthe extremely inelastic instance of demand also or supply in which a portion adjust in price, no issue just how large, results in zero change in the quantity; vertical in appearance

Exercises 4.3

1. Which of the adhering to does NOT impact the magnitude of own-price elasticity of demand?

a) The size of the moment horizon over which we are looking at the adjust in consumer behaviour.b) The availcapacity (or absence thereof) of cshed substitutes for the good in question.c) The amount through which quantity supplied will certainly readjust as price alters.d) All of the above impact the own-price elasticity of demand.

2. If a demand also curve is VERTICAL, then own-price elasticity of demand for this great is equal to:

a) Infinity.b) Zero.c) One.d) None of the above.

3. If – provided consumer preferences – a specific excellent has many type of close substitutes available, then:

a) The demand also for that excellent will certainly be reasonably inelastic, compared to products for which tbelow are few cshed substitutes.b) The supply of that great will be fairly inelastic, compared to products for which tright here are few close substitutes.c) The demand also for that excellent will be reasonably elastic, compared to items for which tbelow are few cshed substitutes.d) The supply of that excellent will certainly be fairly elastic, compared to goods for which there are few close substitutes.


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If – provided consumer choices – a particular excellent has few close substitutes accessible, then:

a) The demand for that good will certainly be relatively inelastic, compared to goods for which tright here are many type of close substitutes.b) The supply of that excellent will be fairly inelastic, compared to products for which there are many close substitutes.c) The demand also for that great will be fairly elastic, compared to items for which tright here are many close substitutes.d) The supply of that great will certainly be reasonably elastic, compared to goods for which there are many type of close substitutes.