5 Elastisitas dan Aplikasi P R I N C I P L E S O F

Presentasi berjudul: "5 Elastisitas dan Aplikasi P R I N C I P L E S O F"— Transcript presentasi:

1 5 Elastisitas dan Aplikasi P R I N C I P L E S O F
F O U R T H E D I T I O N 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. Please be assured that this PowerPoint presentation is, nonetheless, very consistent with the textbook.

2 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

3 Budi memliki bisnis usaha teh. Harga teh per Kg adalah sebesar Rp2
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 Hukum permintaan mengatakan bahwa Budi tidak akan bisa menjual banyak teh, jika Budi menaikkan harga. Berapa banyak teh yang terjual? Bagaimana pendapatan Budi? Skenario We will follow this scenario throughout the first section of this chapter (the section on price elasticity of demand) to illustrate and motivate several important concepts, such as the impact of price changes on sales and revenue. CHAPTER 5 ELASTICITY AND ITS APPLICATION

4 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. Here, Qd and Qs are short for quantity demanded and quantity supplied, as in the PowerPoint for Chapter 4. CHAPTER 5 ELASTICITY AND ITS APPLICATION

5 Elastisitas Permintaan Terhadap Harga
Elastisitas permintaan terhadap harga = Persentase perubahan Qd Persentase perubahan P Besaran persentase perubahan komoditas yang diminta yang disebabkan perubahan P sebesar satu persen. Secara sederhana, hal ini mengukur sensitivitas harga dari permintaan konsumen. CHAPTER 5 ELASTICITY AND ITS APPLICATION

6 Elastisitas Permintaan Terhadap Harga
Price elasticity of demand = Percentage change in Qd Percentage change in P P Q contoh: D P meningkat 10% Elastisitas permintaan terhadap harga sebesar P2 Q2 P1 Q1 15% 10% = 1.5 Q turun15% CHAPTER 5 ELASTICITY AND ITS APPLICATION

7 Elastisitas Permintaan Terhadap Harga
Price elasticity of demand = Percentage change in Qd Percentage change in P P Q 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 D P2 Q2 P1 Q1 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. To be consistent with the text, the last statement in the green box says that we will report all price elasticities as positive numbers. It might be slightly more accurate to say that we will report all elasticities as non-negative numbers: we want to allow for the (admittedly rare) case of zero elasticity. CHAPTER 5 ELASTICITY AND ITS APPLICATION

8 Kalkulasi Perubahan Persentase
Metode standar yang digunakan untuk mengukur perubahan(%): Permintaan Teh P Q Nilai akhir – Nilai awal Nilai awal x 100% Rp2500 8 B D A ke B, perubahan persentase P; Rp2000 12 A (2500–2000)/2000 = 25% CHAPTER 5 ELASTICITY AND ITS APPLICATION

9 Kalkulasi Perubahan Persentase
Problem: Metode standar memberikan hasil yang berbeda bergantung pada nilai awal yang diambil. Permintaan teh P Q AB, P naik 25%, Q turun 33%, elastisitas= 33/25 = 1.33 B A, P turun 20%, Q naik 50%, elastisitas = 50/20 = 2.50 Rp2500 8 B D Rp2000 12 A CHAPTER 5 ELASTICITY AND ITS APPLICATION

10 Kalkulasi Perubahan Persentase
Maka, kita akan menggunakan midpoint method: end value – start value midpoint x 100% Midpoint adalah nilai rata-rata dari nilai awal dan akhir CHAPTER 5 ELASTICITY AND ITS APPLICATION

11 Kalkulasi Perubahan Persentase
Menggunakan metode midpoint, perubahan persentase P adalah 2500 – 2000 2250 x 100% = 22.2% Perubahan persentase Q adalah 12 – 8 10 x 100% = 40.0% These calculations are based on the example shown a few slides back: points A and B on the website demand curve. Elastisitas permnitaan terhadap harga adalah 40/22.2 = 1.8 CHAPTER 5 ELASTICITY AND ITS APPLICATION

12 A C T I V E L E A R N I N G 1: Hitung Elastisitas Berikut
Menggunakan informasi dibawah ini, hitung elastisitas permintaan terhadap harga untuk sebuah kamar hotel: jika P = $70, Qd =5000 jika P = $90, Qd =3000 11

13 A C T I V E L E A R N I N G 1: jawaban
Menggunakan metode midpoint % perubahan Qd (5000 – 3000)/4000 = 50% % perubahan P ($90 – $70)/$80 = 25% Elastisitas permintaan terhadap harga adalah 50% 25% = 2.0 12

14 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. 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. See notes on the next slide for a good suggestion. CHAPTER 5 ELASTICITY AND ITS APPLICATION

15 Contoh 1: Minuman Teh vs Minyak Tanah
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. Suggestion: For each of these examples, display the slide title (which lists the two goods) and the first two lines of text (which ask which good experiences the biggest drop in demand in response to a 20% price increase). Give your students a quiet minute to formulate their answers. Then, ask for volunteers. CHAPTER 5 ELASTICITY AND ITS APPLICATION

16 Conoth 2: “Blue Jeans” vs. “Clothing”
Harga kedua barang meningkat 20%. 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 . 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. In the second scenario, the price of all clothing rises by 20%, and we observe the percentage decrease in demand for all clothing. CHAPTER 5 ELASTICITY AND ITS APPLICATION

17 Contoh 3: Insulin vs. Pesiar Caribbean
Harga kedua barang meningkat 20%. 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) CHAPTER 5 ELASTICITY AND ITS APPLICATION

18 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. CHAPTER 5 ELASTICITY AND ITS APPLICATION

19 Ringkasan Elastisitas permintaan terhadap harga bergantung pada:
Elastisitas permintaan terhadap harga bergantung pada: 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 This slide is a convenience for your students, and replicates a similar table from the text. If you’re pressed for time, it is probably safe to omit this slide from your presentation. CHAPTER 5 ELASTICITY AND ITS APPLICATION

20 Variasi Dari Kurva Permintaan
Ekonom mengklasifikasikan kurva permintaan sesuai dengan elastisitasnya. 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. CHAPTER 5 ELASTICITY AND ITS APPLICATION

21 “ Kurva Permintaan Inelastis Sempurna”
Price elasticity of demand = % change in Q % change in P 0% = 0 10% D curve: P Q D vertikal Q1 P1 Consumers’ price sensitivity: P2 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. However, if elasticity is very close to zero, then the demand curve is almost vertical. In such cases, the convenience of modeling demand as perfectly inelastic probably outweighs the cost of being slightly inaccurate. P turun 10% Elastisitas: Q berubah 0% CHAPTER 5 ELASTICITY AND ITS APPLICATION

22 “Permintaan Inelastis”
Price elasticity of demand = % change in Q % change in P < 10% < 1 10% D D curve: P Q relatif curam Q1 P1 Consumers’ price sensitivity: P2 Q2 relatively rendah 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. P turun 10% Elasticity: < 1 Q naik kurang dari 10% CHAPTER 5 ELASTICITY AND ITS APPLICATION

23 Price elasticity of demand
“Unit Elastic Demand” Price elasticity of demand = % change in Q % change in P 10% = 1 10% D D curve: P Q intermediate slope Q1 P1 Consumers’ price sensitivity: P2 Q2 intermediate 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. This is also the case where price changes have no effect on revenue. P falls by 10% Elasticity: 1 Q rises by 10% CHAPTER 5 ELASTICITY AND ITS APPLICATION

24 Price elasticity of demand
“Elastic demand” Price elasticity of demand = % change in Q % change in P > 10% > 1 10% D D curve: P Q relatif datar Q1 P1 Consumers’ price sensitivity: P2 Q2 relatively tinggi A good example here would be Rice Krispies, or nearly anything with readily available substitutes. An elastic demand curve is flatter than a unit elastic demand curve (which itself is flatter than an inelastic demand curve). P falls by 10% Elasticity: > 1 Q rises more than 10% CHAPTER 5 ELASTICITY AND ITS APPLICATION

25 “Perfectly elastic demand” (the other extreme)
Price elasticity of demand = % change in Q % change in P any % = infinity 0% D curve: P Q horizontal P2 = P1 D Consumers’ price sensitivity: Q1 Q2 extreme “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. Why is the demand curve facing an individual producer perfectly elastic? Recall that elasticity is greater when lots of close substitutes are available. In this case, you are selling a product that has many perfect substitutes: the wheat sold by every other farmer is a perfect substitute for the wheat you sell. P changes by 0% Elasticity: infinity Q changes by any % CHAPTER 5 ELASTICITY AND ITS APPLICATION

26 Elastisitas Kurva Permintaan Linear
P Q $30 20 10 $0 40 60 200% 40% = 5.0 E = 67% = 1.0 E = 40% 200% = 0.2 E = 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. The lesson here is that elasticity falls as you move downward & rightward along a linear demand curve. CHAPTER 5 ELASTICITY AND ITS APPLICATION

27 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. 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. To most of your students, it should be clear that making the best possible decision would require information about the likely effects of the price increase on revenue. That is why elasticity is so helpful, as we will now see…. CHAPTER 5 ELASTICITY AND ITS APPLICATION

28 Elastisitas Harga dan Penerimaan Total
Price elasticity of demand = Percentage change in Q Percentage change in P Revenue = P x Q Jika permintaan adalah elastis, maka Elastisitas permintaan terhadap P > 1 persentase perubahan Q > persentase perubahan P CHAPTER 5 ELASTICITY AND ITS APPLICATION

29 Elastisitas Harga dan Penerimaan Total
Elastic demand (elasticity = 1.8) Peningkatan pendapatan karena P yang lebih besar Demand Teh P Q Hilangnya pendapatan karena Q lebih rendah 2000 12 P = 2000, Q = 12 and revenue = 24000 D 2500 8 P = 2500, Q = 8 and revenue = 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! Point out to students that the area (outlined in blue) representing lost revenue due to lower Q is larger than the area (outlined in yellow) representing increased revenue due to higher P. Hence, the net effect is a fall in revenue. Ketika D elastis, peningkatan harga menyebabkan penurunan pendapatan CHAPTER 5 ELASTICITY AND ITS APPLICATION

30 Elastisitas Harga dan Penerimaan Total
Price elasticity of demand = Percentage change in Q Percentage change in P Revenue = P x Q Demand inelastis, maka Elastisitas permintaan terhadap P< 1 % perubahan Q < % perubahan P CHAPTER 5 ELASTICITY AND ITS APPLICATION

31 Elastisitas Harga dan Penerimaan Total
Now, demand is inelastic: elasticity = 0.82 Peningkatan pendapatan karena P lebih besar Demand teh P Q Pendapatan yang hilang, karena Q lebih rendah 2000 12 Jika P = Rp2000, Q = 12 dan revenue = Rp D 2500 10 P = Rp2500, Q = 10 dan revenue = Rp 25000 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. The knife-edge case, not shown here but worth mentioning in class, is unit-elastic demand. In that case, an increase in price leaves revenue unchanged: the increase in revenue from higher P exactly offsets the lost revenue due to lower Q. Ketika D inelastis, peningkatan harga menyebabkan peningkatan pendapatan CHAPTER 5 ELASTICITY AND ITS APPLICATION

32 A C T I V E L E A R N I N G 2: Elastisitas dan pengeluaran/pendapatan
A. Apotik menaikkan harga insulin sebesar 10%. Apakah total pengeluaran meningkat atau turun? B. Hasil dari perang tarif, harga sebuah kapal pesiar mewah turun 20%. Apakah total pendapatan perusahaan pesiar naik atau turun? These problems, perhaps similar to those you might ask on an exam, are complex in that they test several skills at once: Students must determine whether demand for each good is elastic or inelastic, and they must determine the impact of a price change on revenue/expenditure. So far, we’ve been talking about how elasticity determines the effects of an increase in P on revenue. Part (b) asks your students to determine the effects of a decrease in P. 31

33 A C T I V E L E A R N I N G 2: Answers
A. Apotik meningkatkan harga insulin 10%. Apakah total pengeluaran naik atau turun? Expenditure = P x Q demand adalah inelastis, Q akan turun kurang dari 10%, sehingga expenditure rises. 32

34 A C T I V E L E A R N I N G 2: Answers
B. Revenue = P x Q turunnya harga P menurunkan pendapatan, tapi Q meningkat, pendapatan meningkat. Efek mana yang lebih besar? demand elastis, Q akan meningkat lebih dari 20%, revenue rises. The first part of the explanation discusses the opposing effects on revenue; its purpose is to clarify the effects of a price decrease on revenue, as we have previously only discussed the effects of a price increase. 33

35 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 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. However, I encourage you to consider teaching this application right here - immediately after the section on price elasticity of demand. It is safe to do so, as this application only requires knowledge of price elasticity of demand. Also, putting the application here breaks up what would otherwise be a very long section of theory with a real-world example that most students find very interesting. Knowing elasticity helps us understand what might otherwise be a counter-intuitive result (that drug interdiction increases drug-related crime rather than reducing it). CHAPTER 5 ELASTICITY AND ITS APPLICATION

36 Policy 1: Interdiction pelarangan mengurangi penawaran akan drugs
pelarangan mengurangi penawaran akan drugs new value of drug-related crime Price of Drugs Quantity of Drugs S2 D1 S1 demand untuk obat-obatan inelastis, peningkatan P lebih dari penurunan Q P2 Q2 initial value of drug-related crime P1 Q1 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. However, if you’d rather strip the slide down a bit, here’s a suggestion: in “Normal” view (which is used to edit slides), you can delete the boxes that represent the initial and new values of drug-related crime, and the accompanying captions. Then, when presenting this slide in class, simply point out (with your mouse cursor, a laser pointer, or even your arms and hands) the areas that represent the initial and new values of drug-related crime. Hasil: Terjadi peningkatan total pengeluaran untuk obat-obatan dan kejahatan drugs CHAPTER 5 ELASTICITY AND ITS APPLICATION

37 Policy 2: Education Edukasi mengurangi permintaan akan drugs.
Edukasi mengurangi permintaan akan drugs. new value of drug-related crime Price of Drugs Quantity of Drugs D2 D1 S P dan Q turun. initial value of drug-related crime P1 Q1 hasil: terjadi penurunan total pengeluaran drugs dan kriminal yang berhubungan dengan drugs P2 Q2 CHAPTER 5 ELASTICITY AND ITS APPLICATION

38 Price Elasticity of Supply
Price elasticity of supply = Percentage change in Qs Percentage change in P 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. Most everything in the “price elasticity of supply” section corresponds to analogous concepts from the “price elasticity of demand” section. So, it is probably safe to move through this section more quickly. CHAPTER 5 ELASTICITY AND ITS APPLICATION

39 Elastisitas Penawaran Terhadap Harga
Price elasticity of supply = Percentage change in Qs Percentage change in P P Q Example: S P rises by 8% Price elasticity of supply equals P2 Q2 Q1 P1 16% 8% = 2.0 Q rises by 16% CHAPTER 5 ELASTICITY AND ITS APPLICATION

40 Variasi Kurva Supply Ekonom mengklasifikasikan kurva penawaran sesuai dengan elastisitasnya. Slope dari kurva penawaran memiliki hubungan yang dekat dengan elastisitas penawaran terhadap harga. Rule of thumb: Semakin datar kurva, elastisitasnya lebih besar. Semakin curam kurva, elastisitasnya lebih kecil. CHAPTER 5 ELASTICITY AND ITS APPLICATION

41 “Perfectly inelastic” (one extreme)
Price elasticity of supply = % change in Q % change in P 0% = 0 10% S curve: P Q S vertikal P2 Sellers’ price sensitivity: P1 P rises by 10% Elasticity: Q1 Q changes by 0% CHAPTER 5 ELASTICITY AND ITS APPLICATION

42 Price elasticity of supply
“Inelastic” Price elasticity of supply = % change in Q % change in P < 10% S < 1 10% S curve: P Q Relatif curam P2 Sellers’ price sensitivity: Q2 P1 relatif rendah P rises by 10% Elasticity: Q1 < 1 Q rises less than 10% CHAPTER 5 ELASTICITY AND ITS APPLICATION

43 Price elasticity of supply
“Unit elastic” Price elasticity of supply = % change in Q % change in P 10% = 1 10% S curve: P Q S intermediate slope P2 Sellers’ price sensitivity: Q2 P1 intermediate P rises by 10% Elasticity: Q1 = 1 Q rises by 10% CHAPTER 5 ELASTICITY AND ITS APPLICATION

44 Price elasticity of supply
Price elasticity of supply = % change in Q % change in P > 10% > 1 10% S S curve: P Q Relatif datar P2 Sellers’ price sensitivity: Q2 P1 Relatif tinngi P rises by 10% Elasticity: Q1 > 1 Q rises more than 10% CHAPTER 5 ELASTICITY AND ITS APPLICATION

45 “Perfectly elastic” (the other extreme)
Price elasticity of supply = % change in Q % change in P any % = infinity 0% S curve: P Q horizontal P2 = P1 S Sellers’ price sensitivity: Q1 Q2 extreme P changes by 0% Elasticity: infinity Q changes by any % CHAPTER 5 ELASTICITY AND ITS APPLICATION

46 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 This section is not perfectly analogous to the section on the determinants of the price elasticity of demand, but it’s similar enough that you can probably cover it more quickly and with less hand-holding. CHAPTER 5 ELASTICITY AND ITS APPLICATION

47 A C T I V E L E A R N I N G 3: Elasticity and changes in equilibrium
supply dari beachfront property adalah inelastis. supply dari mobil baru adalah elastis. Pertumbuhan populasi menyebabkan demand kedua barang menjadi dua kali lipat (at each price, Qd doubles). produk yang mana yang akan mengalami perubahan P yang paling banyak ? Produk yang mana yang akan mengalami perubahan Q yang paling banyak? This is one of the “Problems and Applications” at the end of the chapter. 46

48 A C T I V E L E A R N I N G 3: Answers
Beachfront property (supply inelastis): ketika supply inelastis, kenaikan permintaan memiliki dampak yang lebih besar pada harga daripada kuantitas P Q S D1 D2 B Q2 P2 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.] In the text box containing the verbal explanation, “bigger impact” is shorthand for “bigger percentage impact” or “bigger proportional impact.” Q1 P1 A 47

49 A C T I V E L E A R N I N G 3: Answers
Mobil Baru (elastis supply): Ketika supply elastis, kenaikan permintaan memiliki dampak yang lebih besar pada kuantitas dibanding dengan harga. P Q D1 D2 S Q2 P2 B Q1 P1 A 48

50 Bagaimana elastisitas penawaran terhadap harga dapat berubah
Supply menjadi kurang elastis ketika Q naik, karena batas kapasitas. P Q S elastisitas < 1 $15 525 12 500 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. Of course, all of this applies to the short run. In the long run, firms can build more factories, and (depending on the market structure) new firms can enter the market. elastisitas > 1 4 200 $3 100 CHAPTER 5 ELASTICITY AND ITS APPLICATION

51 Elastisitas Pendapatan
Elastisitas permintaan terhadap pendapatan mengukur persentase perubahan Qd yang disebabkan oleh persentase perubahan pendapatan sebesar satu persen Income elasticity of demand = Percent change in Qd Percent change in income This topic and the next one (cross-price elasticity) do not appear anywhere else in the book. Instructors who are pressed for time may consider cutting these topics. (This is not the official position of Greg Mankiw or Thomson/South-Western, it’s just my suggestion.) CHAPTER 5 ELASTICITY AND ITS APPLICATION

52 Elastisitas Pendapatan
Recall chap.4: kenaikan pendapatan menyebabkan kenaikan permintaan pada barang normal. Barang normal, elastisitas pendapatan > 0. Barang inferior , elastisitas pendapatan < 0. Barang mewah, elastistas pendapatan > 1 Barang kebutuhan pokok, elastisitas pendapatan < 1 CHAPTER 5 ELASTICITY AND ITS APPLICATION

53 Elastisitas Silang Elastisitas permintaan harga silang mengukur besaran persentase perubahan Qd disebabkan perubahan harga barang lain sebesar satu persen Cross-price elast. of demand = % change in Qd for good 1 % change in price of good 2 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. CHAPTER 5 ELASTICITY AND ITS APPLICATION

54 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. CHAPTER 5 ELASTICITY AND ITS APPLICATION

55 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.” CHAPTER 5 ELASTICITY AND ITS APPLICATION

56 Ringkasan Bab 5 Elastisitas permintaan terhadap pendapatan mengukur besaran persentase perubahan komoditas yang diminta yang disebabkan oleh perubahan pendapatan konsumen sebesar satu persen. Elastisitas permintaan silang mengukur besaran persentase perubahan komoditas yang disebabkan oleh perubahan harga komoditas lain sebesar satu persen. CHAPTER 5 ELASTICITY AND ITS APPLICATION