Bab 05 Elastisitas Dan Aplikasi

Slide 1© 2007 Thomson South-Western, all rights reserved
N. G R E G O R Y M A N K I W
PowerPoint® Slides by Ron Cronovich
5
Elastisitas dan Aplikasi
P R I N C I P L E S O F
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The elasticity chapter in most principles textbooks is fairly technical, and is not always students’ favorite. This PowerPoint chapter contains several special features designed to engage and motivate students to learn this important material.
First, we consider a scenario in which students face a business decision – whether to raise the price of a service they sell. This scenario is used to illustrate the effects of raising price on number of units sold and on revenue, which students immediately recognize as critical to the business decision.
Second, instead of merely listing the determinants of elasticity, students are asked to think about some concrete examples and deduce from each one a lesson about the determinants of elasticity.
Third, instead of putting the applications at the end of the chapter (as in the textbook), this PowerPoint includes one of them immediately after the section on price elasticity of demand. This helps break up what would otherwise be a long stretch of theory.
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Bab ini akan menjawab beberapa pertanyaan seperti berikut:
Apa yang dimaksud dengan elastisitas? Kasus seperti apa yang dapat membantu kita dalam memahami elastisitas?
Apa yang dimaksud dengan price elasticity of demand ?
Bagaimana hal tersebut dihubungkan dengan kurva permintaan?
Bagaimana hubungannya dengan pendapatan dan pengeluaran?
Apa yang dimaksud dengan price elasticity of supply?
Bagaimana hubungannya terhadap kurva penawaran?
Apa yang dimaksud dengan elastisitas pendapatan dan elastisitas harga silang?
CHAPTER 5 ELASTICITY AND ITS APPLICATION
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Budi memliki bisnis usaha teh. Harga teh per Kg adalah sebesar Rp2.000, dan mampu menjual (misalnya)12 Kg teh per bulan.
Kemudian terjadi peningkatan biaya produksi sehingga Budi menaikan harga menjadi Rp 2.500.
Hukum permintaan mengatakan bahwa Budi tidak akan bisa menjual banyak teh, jika Budi menaikkan harga. Berapa banyak teh yang terjual? Bagaimana pendapatan Budi?
Skenario
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Elastisitas
elastisitas mengukur berapa besaran persentase perubahan satu variabel yang disebabkan perubahan variabel lain sebesar satu persen.
Elastisitas angka yang menunjukan respon dari Qd atau Qs terhadap faktor penentu.
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Elastisitas Permintaan Terhadap Harga
Besaran persentase perubahan komoditas yang diminta yang disebabkan perubahan P sebesar satu persen.
Secara sederhana, hal ini mengukur sensitivitas harga dari permintaan konsumen.
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Sepanjang kurva D, P dan Q bergerak dengan arah yang berlawanan, sehingga akan memiliki nilai negatif.
Kita akan menghilangkan nilai negatif, karena nilai elastisitas harga bernilai positif
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P
Q
D
Q2
P2
P1
Q1
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It might be worth explaining to your students that “P and Q move in opposite directions” means that the percentage change in Q and the percentage change in P will have opposite signs, thus implying a negative price elasticity.
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Kalkulasi Perubahan Persentase
A ke B,
perubahan persentase P;
(2500–2000)/2000 = 25%
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Problem:
Metode standar memberikan hasil yang berbeda bergantung pada nilai awal yang diambil.
AB,
elastisitas= 33/25 = 1.33
P
Q
D
Rp2500
8
B
Rp2000
12
A
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0
end value – start value
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0
2500 – 2000
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A C T I V E L E A R N I N G 1:
Hitung Elastisitas Berikut
jika P = $70, Qd =5000
jika P = $90, Qd =3000
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jawaban
(5000 – 3000)/4000 = 50%
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Apa Saja yang Menentukan Elastisitas Harga?
Untuk mempelajari hal-hal yang mempengaruhi elastisitas harga, kita akan menggunakan dua barang.Dengan kasus harga kedua barang meningkat 20%. Hal apa saja yang dapat kita pelajari.
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In essence, the textbook says “Here are the determinants of elasticity. The first one is availability of close substitutes. Here’s an example….”
That’s great for a textbook. For teaching, I’ve found a different approach to be far more effective – the approach on the following four slides, which essentially has students deduce the general lessons from specific examples that students can probably figure out with a little common sense.
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Contoh 1:
Harga dari kedua barang meningkat 20%.
Minuman Teh memiliki banyak barang substitusi ( Coca Cola, Nescafe, dan Milk kuat),
sehingga pembeli dengan mudah berganti jika terjadi kenaikan harga.
Minyak tanah tidak banyak memiliki barang substitusi, maka konsumen akan membeli dengan jumlah yang sedikit jika harga meningkat.
kesimpulan: Elastisitas harga akan lebih besar ketika barang substitusi tersedia.
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Conoth 2:
Komoditas mana yang akan terjadi penurunan permintaan paling banyak? Kenapa?
blue jeans (narrowly defined), memiliki banyak barang substitusi (celana pendek, ¾ atau lainnya).
Sedikit barang substitusi yang tersedia untuk barang yang broadly defined.
(Dapatkah Anda memikirkan pengganti untuk pakaian?)
Kesimpulan: Elastisitas harga lebih tinggi untuk barang yang narrowly defined daripada broadly defined .
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You might need to clarify the nature of this thought experiment.
Here, we look at two alternate scenarios. In the first, the price of blue jeans (and no other clothing) rises by 20%, and we observe the percentage decrease in quantity of blue jeans demanded.
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Contoh 3:
Komoditas mana yang akan terjadi penurunan permintaan paling banyak? Kenapa?
Untuk jutaan penderita diabetes, insulin adalah keharusan atau kebutuhan. Kenaikan harga akan menyebabkan penurunan permintaan sedikit atau tidak ada penurunan.
Pesiar adalah barang mewah. Jika harga meningkat, bebarapa orang akan melepaskannya
Kesimpulan: Elastisitas harga lebih tinggi untuk barang luxuries (mewah) daripada barang necessities (kebutuhan/keharusan)
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Contoh 4:
Bahan Bakar (Short Run) vs. Bahan Bakar (Long Run)
Harga bahan bakar meningkat 20%. Dalam kondisi short run atau long run, manakah yang mengalami penurunan permintaan yang lebih banyak? Mengapa?
Tidak banyak yang dapat dilakukan orang didalam jangka pendek, selain menggunakan bus.
Di jangka pankang, individu dapat membeli mobil kecil atau tinggal lebih dekat dengan tempat kerja.
Kesimpulan: Elastisitas Harga lebih besar dalam jangka panjang daripada jangka pendek.
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Ringkasan
Sejauh mana tersedianya barang substitusi
barang necessity atau luxury
Seberapa luas (broadly) atau sempit (narrowly) barang tersebut didefinisikan
Time horizon: elastisitas lebih besar pada jangka panjang daripada jangka pendek
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This slide is a convenience for your students, and replicates a similar table from the text.
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Variasi Dari Kurva Permintaan
Elastisitas permintaan terhadap harga berkaitan dengan slope dari kurva permintaan
Aturan pada umumnya: kurva yang lebih flat, elastisitasnya lebih besar. Kurva yang lebih curam, elastisitasnya lebih kecil.
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“ Kurva Permintaan Inelastis Sempurna”
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If Q doesn’t change, then the percentage change in Q equals zero, and thus elasticity equals zero.
It is hard to think of a good for which the price elasticity of demand is literally zero. Take insulin, for example. A sufficiently large price increase would probably reduce demand for insulin a little, particularly among people with very low incomes and no health insurance.
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“Permintaan Inelastis”
0
< 10%
10%
< 1
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An example: student demand for textbooks that their professors have required for their courses.
Here, it’s a little more clear that elasticity would be small, but not zero. At a high enough price, some students will not buy their books, but instead will share with a friend, or try to find them in the library, or just take copious notes in class.
Another example: gasoline in the short run.
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“Unit Elastic Demand”
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This is the intermediate case: the demand curve is neither relatively steep nor relatively flat. Buyers are neither relatively price-sensitive nor relatively insensitive to price.
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“Elastic demand”
0
> 10%
10%
> 1
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P1
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“Extreme price sensitivity” means the tiniest price increase causes demand to fall to zero.
“Q changes by any %” – when the D curve is horizontal, the quantity is indeterminant. Consumers might demand Q1 units one month, Q2 units another month, and some other quantity later. Q can change by any amount, but P always “changes by 0%” (i.e. doesn’t change).
If perfectly inelastic is one extreme, this (perfectly elastic) is the other.
Here’s a good real-world example of a perfectly elastic demand curve, which foreshadows an upcoming chapter on firms in competitive markets. Suppose you run a small family farm in Iowa. Your main crop is wheat. The demand curve in this market is downward-sloping, and the market demand and supply curves determine the price of wheat. Suppose that price is $5/bushel.
Now consider the demand curve facing you, the individual wheat farmer. If you charge a price of $5, you can sell as much or as little as you want. If you charge a price even just a little higher than $5, demand for YOUR wheat will fall to zero: Buyers would not be willing to pay you more than $5 when they could get the same wheat elsewhere for $5. Similarly, if you drop your price below $5, then demand for YOUR wheat will become enormous (not literally infinite, but “almost infinite”): if other wheat farmers are charging $5 and you charge less, then EVERY buyer will want to buy wheat from you.
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Elastisitas Kurva Permintaan Linear
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The material on this slide is not used anywhere else in the textbook. Therefore, if you are pressed for time and looking for things to cut, you might consider cutting this slide. (Note that this is my personal recommendation and is not necessarily the official position of Greg Mankiw or Thomson/South-Western.)
Due to space limitations, this slide uses “E” as an abbreviation for elasticity, or more specifically, the price elasticity of demand, and the slide omits the analysis of revenue along the demand curve.
Calculations of percentage changes use the midpoint method. (This is why the increase from Q=0 to Q=20 is 200% rather than infinity.)
As you move down a linear demand curve, the slope (the ratio of the absolute change in P to that in Q) remains constant:
From the point (0, $30) to the point (20, $20), the “rise” equals -$10, the “run” equals +20, so the slope equals -1/2 or -0.5.
From the point (40, $10) to the point (60, $0), the “rise” again equals -$10, the “run” equals +20, and the slope again equals -0.5.
However, the percentage changes in these variables do not remain constant, as shown by the different colored elasticity calculations that appear on the slide.
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Elastisitas Harga dan Penerimaan Total
Melanjutkan skenario, jika Budi meningkatkan harga dari 2000 ke 2500, akankah pendapatannya meningkat atau turun?
TR= P x Q
harga yang meningkat akan memiliki dua dampak terhadap pendapatan:
P yang lebih besar berarti akan memiliki pendapatan yang lebih untuk setiap unit yang terjual.
Tapi individu akan menjual unit lebih sedikit. (Law of Demand).
Manakah efek yang paling besar? Hal ini bergantung pada elastisitas permintaan terhadap harga.
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We return to our scenario. It’s not hard for students to imagine being in this position – running their own business and trying to decide whether to raise the price.
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Jika permintaan adalah elastis, maka
Elastisitas permintaan terhadap P > 1
persentase perubahan Q > persentase perubahan P
Revenue = P x Q
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Elastic demand
(elasticity = 1.8)
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Peningkatan pendapatan karena P yang lebih besar
Demand Teh
2500
8
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In the “Normal” view (edit mode), the labels over the graph look cluttered, like they’re on top of each other. This is not a mistake – in “Slide Show” mode (presentation mode), they will be fine – try it!
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Demand inelastis, maka
% perubahan Q < % perubahan P
Revenue = P x Q
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Now, demand is inelastic:
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Peningkatan pendapatan karena P lebih besar
Demand teh
2500
10
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Again, the slide appears cluttered in “Normal” view (edit mode), but everything is fine when displayed in “Slide Show” mode (presentation mode).
Point out to students that the area representing lost revenue due to lower Q is smaller than the area representing increased revenue due to higher P. Hence, the net effect is an increase in revenue.
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Elastisitas dan pengeluaran/pendapatan
A. Apotik menaikkan harga insulin sebesar 10%. Apakah total pengeluaran meningkat atau turun?
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Answers
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A. Apotik meningkatkan harga insulin 10%. Apakah total pengeluaran naik atau turun?
Expenditure = P x Q
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Answers
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Aplikasi: Ketika ada kebijakan pelarangan drugs, apa yang terjadi dengan kriminal yang berhubungan dengan drugs ? meningkat atau menurun?
Salah satu efek samping dari penggunaan drugs adalah kejahatan: Pengguna sering berpaling kepada kejahatan untuk membiayai kebiasaan mereka.
Kita memeriksa dua kebijakan yang dirancang untuk mengurangi penggunaan drugs dan melihat apa efeknya terhadap kriminal yang berhubungan dengan drugs.
Untuk mempermudah, kita asumsikan nilai total rupiah dari kejahatan drugs sama dengan total pengeluaran pada drugs.
Permintaan untuk illegal drugs adalah inelastis, karena ada ketergantungan/kecanduan
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In the textbook, this application appears near the end of the chapter, and you can easily move these slides to the end if you wish to teach things in the same order as the book.
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Policy 1: Interdiction
demand untuk obat-obatan inelastis, peningkatan P lebih dari penurunan Q
Hasil: Terjadi peningkatan total pengeluaran untuk obat-obatan dan kejahatan drugs
Price of Drugs
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By the time all elements have appeared on the screen, the slide will look kind of busy. I think this is okay, because the elements appear on the screen one by one, so students have time to absorb each one before the next one appears.
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Policy 2: Education
P dan Q turun.
terjadi penurunan total pengeluaran drugs dan kriminal yang berhubungan dengan drugs
Price of Drugs
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Price Elasticity of Supply
Price elasticity of supply mengukur seberapa besar respon Qs terhadap perubahan P.
Secara sederhana, hal ini mengukur sensitivitas harga dari sisi supply
Menggunakan midpoint method untuk menghitung persentase perubahan.
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Elastisitas Penawaran Terhadap Harga
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Variasi Kurva Supply
Slope dari kurva penawaran memiliki hubungan yang dekat dengan elastisitas penawaran terhadap harga.
Rule of thumb:
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“Perfectly inelastic” (one extreme)
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“Inelastic”
Q1
P1
0
< 10%
10%
< 1
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“Unit elastic”
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“Elastic”
Q1
P1
0
> 10%
10%
> 1
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“Perfectly elastic” (the other extreme)
P1
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Faktor Penentu Elastisitas Penawaran
Semakin besar elastisitas penawaran terhadap harga, para penjual lebih mudah untuk menjual kuantitas produksinya.
Contoh: Supply beachfront property lebih sulit untuk berubah dan kurang elastis dibandingkan dengan supply dari mobil baru.
Untuk jumlah barang yang banyak, elastisitas penawaran terhadap harga lebih besar di jangka panjang dibandingkan dengan jangka pendek, karena perusahaan dapat membangun pabrik baru atau perusahan baru yang masuk kedalam pasar
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Elasticity and changes in equilibrium
supply dari beachfront property adalah inelastis. supply dari mobil baru adalah elastis.
Pertumbuhan populasi menyebabkan
(at each price, Qd doubles).
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Answers
kenaikan permintaan memiliki dampak yang lebih besar pada harga daripada kuantitas
P
Q
D1
D2
S
Q1
P1
A
B
Q2
P2
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In this slide and the next, the initial price and quantity and the two demand curves are the same. The only difference is the elasticity of supply and slope of the supply curve.
[The D curve shifts to the right, but not in a parallel fashion: at each price, quantity demanded is twice as high, so the new D curve will be flatter than the initial one.]
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Answers
kenaikan permintaan memiliki dampak yang lebih besar pada kuantitas dibanding dengan harga.
P
Q
D1
D2
S
Q1
P1
A
Q2
P2
B
Bagaimana elastisitas penawaran terhadap harga dapat berubah
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This graph replicates the one in Figure 6. Note: The graph here is not quite drawn to scale.
When the price rises from $3 to $4 (a 29% increase, using the midpoint method), quantity rises from 100 to 120 (or 67%). Because 67% > 29%, price elasticity of supply is greater than one. When the price rises from $12 to $15 (22%), quantity rises from 500 to 525 (about 5%), so price elasticity of supply is less than one.
The way I like to explain this is as follows:
When output is very low, it is relatively easy for firms to increase output. They may have excess capacity, or they are not requiring full effort from their workers. Increasing output is not difficult, so it doesn’t take much of an increase in price to induce an increase in production.
When output is very high, it is relatively expensive for firms to increase output further: there’s little or no excess capacity, they are already running their factories and machines at a high level of intensity. To increase output further, they might have to pay their workers overtime, and their machines experience more wear and tear and therefore require more repairs. So, at high levels of output, it takes a much larger price increase to make firms willing to increase output further.
Eventually, firms bump up against their capacity constraints, and simply cannot increase output in response to further price increases.
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Elastisitas Pendapatan
Percent change in Qd
Percent change in income
Income elasticity of demand
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Barang normal, elastisitas pendapatan > 0.
Barang inferior , elastisitas pendapatan < 0.
Barang mewah, elastistas pendapatan > 1
Barang kebutuhan pokok, elastisitas pendapatan < 1
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Elastisitas Silang
substitusi, elastisitas harga silang > 0
kenaikan harga beef disebabkan kenaikan permintaan ayam.
komplemen, elastisitas harga silang < 0
kenaikan harga komputer disebabkan penurunan permintaan untuk software.
% change in Qd for good 1
% change in price of good 2
Cross-price elast.
of demand
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Ringkasan Bab 5
Elastisitas mengukur respon Qd atau Qs terhadap salah satu faktor penentu.
Elastisitas permintaan terhadap harga sama dengan persentase perubahan Qd dibagi dengan persentase perubahan P.
Ketika nilainya <1, demand “inelastis.” ketika nilainya >1, demand “elastis.”
ketika demand inelastis, pendapatan total naik ketika harga naik. Ketika demand elastis, pendapatan total justru turun ketika harga naik.
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Ringkasan Bab 5
Permintaan kurang elastis pada kondisi jangka pendek, barang kebutuhan, barang broadly defined, atau dengan barang substitusi.
Elastisitas penawaran terhadap harga sama dengan persentase perubahan Qs dibagi dengan persentase perubahan P.
Ketika nilainya < 1, supply adalah “inelastis.” ketika nilainya > 1, supply adalah “elastis.”
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Ringkasan Bab 5
Elastisitas permintaan silang mengukur besaran persentase perubahan komoditas yang disebabkan oleh perubahan harga komoditas lain sebesar satu persen.
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Bab 05 Elastisitas Dan Aplikasi

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