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Elasticities model essay

Explain what might cause price elasticity of demand and cross elasticity of demand to vary for different products.

Essay, part (a) [10] · H2 Economics

This model essay is by Mr Eugene Toh, author of the H1 and H2 A Level Economics TYS answer keys, published by SAP and sold at Popular, and of 50 Model Essays (Shing Lee).

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The model thesis in brief

PED varies across products mainly with the degree of necessity, the share of income a good takes, and the availability of substitutes. XED varies with the relationship between goods: positive for substitutes such as feather and nylon shuttlecocks, and negative for complements such as rackets and shuttlecocks.

Examiner's note: what makes this an A

This 10-mark part is a determinants question, so the answer should define PED and XED, then explain the factors that move each, using the shuttlecock context to keep the illustration concrete rather than abstract.

For PED, develop the three standard determinants with application: necessity (professional players treat feather shuttlecocks as essential, so demand is more inelastic), the proportion of income spent (a large or rising share makes demand more elastic), and the availability of substitutes (cheaper nylon shuttlecocks make demand more elastic).

For XED, the determinant is the nature of the relationship: substitutes give a positive XED whose size depends on closeness, while complements give a negative XED. Using feather versus nylon shuttlecocks for the positive case and rackets versus shuttlecocks for the negative case shows the examiner you can apply the concept both ways.

Introduction

Price elasticity of demand (PED) measures the responsiveness of the quantity demanded of a good to a change in its own price, ceteris paribus, while cross elasticity of demand (XED) measures how the quantity demanded of one good responds to a change in the price of another good. In the context of rising feather-shuttlecock prices in China, where shuttlecocks are made from duck and goose feathers, the PED and XED of different products may vary significantly for several reasons.

Price elasticity of demand

PED varies across products for several reasons. For feather shuttlecocks, PED reflects how sensitive the demand for shuttlecocks is to changes in their price, calculated as the percentage change in quantity demanded over the percentage change in price, with the sign negative due to the inverse relationship between price and quantity demanded.

If the PED for feather shuttlecocks is inelastic (PED less than 1), a price increase such as the recent 40% rise would lead to a less than proportionate fall in quantity demanded. This could reflect the necessity of shuttlecocks for badminton players, who may not reduce consumption significantly despite higher prices. If demand is elastic (PED greater than 1), a price rise would cause a larger drop in quantity demanded, which might occur if alternatives such as nylon shuttlecocks are readily available.

Several factors influence PED. First, the degree of necessity: for professional players who prefer feather shuttlecocks for their superior quality, demand may be more inelastic, since they are essential for performance, whereas recreational players may find them less essential and switch to cheaper alternatives, making demand more elastic. Second, the proportion of income spent: feather shuttlecocks, being more expensive, may represent a significant portion of a frequent player's budget, so if prices keep rising, demand may become more elastic as consumers grow more sensitive to price changes. Third, the availability of substitutes: nylon shuttlecocks, which are cheaper and more durable, could serve as substitutes, so if players find their performance acceptable, the demand for feather shuttlecocks becomes more elastic as consumers can switch in response to a price rise.

Cross elasticity of demand

Cross elasticity of demand examines how the demand for one product responds to a price change in another, helping us understand the relationship between feather shuttlecocks and other goods such as nylon shuttlecocks. XED can be positive or negative, depending on whether goods are substitutes or complements.

Feather and nylon shuttlecocks are substitutes, so their XED would likely be positive: a 40% increase in the price of feather shuttlecocks may raise the demand for nylon shuttlecocks, depending on how close the substitutes are. If they are not perfect substitutes, the XED is positive but relatively low, so the shift in demand might not be dramatic; if players find nylon shuttlecocks a viable alternative, the XED could be higher, indicating a stronger substitution effect.

On the other hand, badminton rackets and shuttlecocks are complements. A rise in the price of shuttlecocks might reduce the demand for rackets, especially among casual players who might forgo the sport altogether due to higher costs. This relationship would be reflected in a negative XED, showing the complementary nature of these goods.

Conclusion

PED and XED can vary widely depending on factors such as the degree of necessity, the proportion of income spent, the availability of substitutes, and the relationship between goods. In the case of rising feather-shuttlecock prices, these factors influence how players respond to price changes and whether they switch to alternatives such as nylon shuttlecocks. Understanding these variations is important for businesses in the shuttlecock market when making pricing and production decisions.

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Master the theory behind this essay

Revise the tools this answer uses: YED and XED, PED and PES, Demand and Supply Analysis. See the full Elasticities notes, the A Level Economics notes and the glossary.

Questions students ask

What makes the PED of a product more elastic?

Demand tends to be more elastic when a good is less of a necessity, takes up a larger share of income, and has close, available substitutes. For feather shuttlecocks, cheaper nylon alternatives and a rising price share both push demand towards greater elasticity.

Why is XED positive for some pairs and negative for others?

XED is positive for substitutes, such as feather and nylon shuttlecocks, since a price rise in one raises demand for the other, and negative for complements, such as rackets and shuttlecocks, since a dearer shuttlecock reduces demand for rackets.

Are these the official answers?

No. This is a model essay by Mr Eugene Toh, author of the H1 and H2 A Level Economics TYS answer keys published by SAP and sold at Popular. Use it as a guide to structure and rigour, then write it in your own words.

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