MINGGU 5 Elastisitas Prepared by INSAN HASANI Mengukur

MINGGU 5 Elastisitas Prepared by: INSAN HASANI

Mengukur Elastisitas • Mengukur apakah? • Respons atau reaksi • Apakah alasan untuk mengetahuinya? • Respons terhadap Permintaan dan Penawaran adalah substansi yang menjelaskan hal-hal terkait dengan analisis pasar. • Mengapa tidak mengacu pada “slope” atau kemiringan? • Sebagai pembanding antar pasar : inter market • Sebagai pembanding didalam pasar itu sendiri: intra market • “Slope” dapat menimbulkan kesalahpahaman • Suatu unit pengukuran yang bebas

Mengapa “Economists” menggunakan elastisitas • Elastisitas adalah suatu unit pengukuran yang bebas. • Bukanlah suatu hal yang material membandingkan dua pasar melalui harga dan kuantitas dari suatu jenis barang dengan menggunakan elastisitas. • Elastisitas memungkinkan “economists” untuk mengkuantifikasi perbedaan diantara pasar tanpa menstandarisasi unit dari pengukuran.

Apakah elastisitas? • Mengukur persentase dari perubahan satu variabel sebagai hasil dari 1 % perubahan satu variabel lainnya. • Terdiri dari berbagai jenis elastisitas. • 4 jenis yang akan dibahas. • 3 dari fungsi permintaan • 1 dari fungsi penawaran

2 Elastisitas Utama • Elastisitas harga dari permintaan: kepekaan terhadap kuantitas permintaan suatu jenis barang sebagai akibat dari perubahan harga dari barang tersebut. • Elastisitas harga dari penawaran: kepekaan terhadap kuantitas penawaran suatu jenis barang sebagai akibat dari perubahan harga dari barang tersebut. • Keduanya seringkali dimaknai sebagai elastisitas harga.

Contoh dari elastisitas harga dari permintaan • Ketika harga BBM meningkat 1%, kuantitas permintaan terhadap BBM tersebut turun 0. 2%, maka permintaan bensin tidak sangat sensitif terhadap harga. • Elastisitas harga dari permintaan adalah -0. 2. • Ketika harga perhiasan emas meningkat 1%, kuantitas permintaan terhadap perhiasan emas tersebut turun 2. 6%, maka permintaan perhiasan emas sangat sensitif terhadap harga. • Elastisitas harga dari permintaan adalah -2. 6.

Contoh dari elastisitas harga dari penawaran • Ketika harga lukisan Da. Vinci meningkat 1%, kuantitas penawaran terhadap lukisan tersebut tidak berubah, maka penawaran lukisan sepenuhnya tidak sensitif terhadap harga. • Elastisitas harga dari penawaran adalah 0. • Ketika harga daging meningkat 1%, kuantitas penawaran terhadap daging tersebut meningkat 5%, maka penawaran daging sangat sensitif terhadap harga. • Elastisitas harga dari penawaran adalah 5.

Contoh dari unit yang bebas dari perbandingan … 1 • Bensin dan perhiasan • Hal tersebut bukanlah suatu masalah bahwa bensin dijual pergalonnya $1. 09 dan emas dijual per onsnya $290. • Kita membandingkan elastisitas permintaan dari bensin (-0. 2) dan perhiasan emas (-2. 6). • Berdasarkan elastisitas tersebut permintaan perhiasan emas adalah lebih sensitif terhadap perubahan harga.

Contoh dari unit yang bebas dari perbandingan … 2 • Lukisan daging • Hal tersebut bukanlah suatu masalah bahwa lukisan klasik dijual perunitnya jutaan dollar sementara daging sapi dijual per ponnya sekitar $1. 50. • Kita membandingkan elastisitas penawaran dari lukisan klasik (0) dan daging sapi (5). • Berdasarkan elastisitas tersebut penawaran daging sapi lebih sensitif terhadap perubahan harga.

Relasi ekonomi inelastis • Suatu elastisitas adalah kecil jika nilainya antara 0 dan 1 (dalam nilai absolut), kondisi tersebut menggambarkan relasi yang inelastis. • Inelastis permintaan adalah kuantitas permintaan suatu jenis barang sangat tidak sensitif terhadap perubahan harga. • Inelastis penawaran adalah kuantitas penawaran suatu jenis barang sangat tidak sensitif terhadap perubahan harga.

Relasi ekonomi elastis • Suatu elastisitas adalah besar jika nilainya lebih besar dari 1 (dalam nilai absolut), kondisi tersebut menggambarkan relasi yang elastis. • Elastis permintaan adalah kuantitas permintaan suatu jenis barang sensitif terhadap perubahan harga. • Elastis penawaran adalah kuantitas penawaran suatu jenis barang sensitif terhadap perubahan harga.

Size of Price Elasticities Unit elastic Inelastic 0 Elastic 1 2 3 4 5 6 • Unit elastic: own price elasticity equal to 1 u Inelastic: own price elasticity less than 1 u Elastic: own price elasticity greater than 1

General Formula for own price elasticity of demand • P = Current price of good X • XD = Quantity demanded at that price • DP = Small change in the current price • DXD= Resulting change in quantity demanded

Catatan: • Elastisitas harga dari permintaan adalah selalu negatif. • Elastisitas harga dari permintaan nilainya absolut (mengabaikan tanda negatif). • Sehingga, meskipun hasil perhitungan formula menyebutkan bahwa elastisitas harga dari permintaan adalah negatif, maka elastisitas tersebut adalah 0. 2 dalam contoh pertama dan 2. 6 dalam contoh kedua.

Arc Formula untuk Elastisitas - Umum • Meskipun formula eksak untuk menghitung suatu elastisitas berguna secara teori, dalam kenyatannya “economists” biasanya mengunakan pendekatan untuk menghitungnya yang disebut arc elastisitas. • Elastisitas antara dua titik sesungguhnya merupakan pendekatan. • Diperlukan dua titik untuk melakukan penghitungan.

Arc Formula for Own Price Elasticity of Demand • Get two points of the demand curve: Points A and B. • Consider PA and XA and PB and XB from the demand relationship. • Note: we’ll take absolute value

Point Formula for Own Price Elasticity of Demand • The exact formula for calculating an elasticity at the point A on the demand curve. • Note: we’ll take absolute value

Slope of the Demand Curve • DP is the change in price. (DP<0) u DX is the change in quantity. u slope = DP/ DX u 1/slope = DX/ DP Price Demand P P+ DP DP DX X X + DX Quantity

Slope Compared to Elasticity • The slope measures the rate of change of one variable (P, say) in terms of another (X, say). • The elasticity measures the percentage change of one variable (X, say) in terms of another (P, say).

Example: Elasticity Calculation at “A” • Slope = (40 -32)/(10 -14)=-2 • 1/slope = -1/2 • P/X = 36/12 = 3 at point A • P/X x 1/slope = -1. 5 • Elasticity of demand = -1. 5 • Absolute value of the elasticity = 1. 5

Exercise -- Linear Demand • Compute the elasticity at the point indicated in red on the table (X=18, P=24). • Slope = -2 • 1/Slope = -1/2 • P/X = 24/18 = 4/3 • Elasticity = -2/3

Elasticities and Linear Demand • The elasticity varies along a linear demand (or supply) curve. This is illustrated in the linear demand curve table above. • Note: Usually we would report last column as absolute value

Elastisitas Penawaran • Elastisitas harga dari penawaran adalah selalu positif. • Elastistas harga dari penawaran merupakan nilai sebenarnya. . • Cara yang sama digunakan untuk menghitung formula titik dan arc pada elastisitas penawaran sebagaimana elastisitas permintaan.

Beberapa Definisi Terkait Dengan Nilai Ekstrim dari Elastisitas • Economists menggunakan istilah “elastisitas sempurna” dan “inelastis sempurna” untuk menggambarkan nilai ekstrim dari elastisitas harga. • Elastisitas sempurna berarti bahwa kuantitas (permintaan atau penawaran) sensitif terhadap harga. • Inelastis sempurna berarti bahwa kuantitas (permintaan atau penawaran) tidak memiliki sensitifitas terhadap harga.

Perfectly Elastic Demand • We say that demand is perfectly elastic when a 1% change in the price would result in an infinite change in quantity demanded. Price Perfectly Elastic Demand (elasticity = ¥) Quantity

Perfectly Inelastic Demand • We say that demand is perfectly inelastic when a 1% change in the price would result in no change in quantity demanded. Price Perfectly Inelastic Demand (elasticity = 0) Quantity

Perfectly Elastic Supply • We say that supply is perfectly elastic when a 1% change in the price would result in an infinite change in quantity supplied. Price Perfectly Elastic Supply (elasticity = ¥) Quantity

Perfectly Inelastic Supply • We say that supply is perfectly inelastic when a 1% change in the price would result in no change in quantity supplied. Price Perfectly Inelastic Supply (elasticity = 0) Quantity

Determinants of elasticity • What is a major determinant of the own price elasticity of demand? • Availability of substitutes in consumption. • What is a major determinant of the own price elasticity of supply? • Availability of alternatives in production.

Reminders • Value of own price elasticity usually changes along a demand curve • there are many interesting intra elasticity applications • Can also compare elasticities across markets • there are interesting inter elasticity questions

Menggunakan Elastisitas Permintaan: Total Pengeluaran/Belanja • Total pengeluaran atas suatu produk apakah naik atau turun ketika harga meningkat? • Harga naik berarti lebih banyak pengeluaran untuk masing-masing unit. • Tetapi, kuantitas permintaan turun saat harga naik. • Sehingga, kita harus mengukur elastisitas harga dari permintaan untuk menjawab permintaan tersebut.

Contoh: Tarif Tol Jembatan • Tarif tol jembatan the George Washington adalah $2. 00/trip. • Andaikan kuantitas permintaan adalah 100, 000 trips/hour. • Dan elastisitas harga dari permintaan untuk jembatan tersebut adalah 2. 0, Berapakah total pengeluaran jika tarif tol jembatan tetap dan meningkat sebesar 10%? Bandingkan hasil keduanya serta berikan kesimpulan!!

Bridge Toll: Elastic Demand • Price elasticity of demand = 2. 0 • Toll increase of 10% implies a 20% decline in the quantity demanded. • Trips fall to 80, 000/hour. • Total expenditure falls to $176, 000/hour (= 80, 000 x $2. 20). • $176, 000 < $200, 000, the revenue from a $2. 00 toll.

Contoh Tarif Tol Jembatan, Bagian 2 • Sekarang andaikan elastisitas dari permintaan adalah 0. 5. • Bagaimana jumlah dari perjalanan dan pengeluaran tol dipengaruhi oleh peningkatan 10% tarif tol?

Bridge Toll: Inelastic Demand • Price elasticity of demand = 0. 5 • Toll increase of 10% implies a 5% decline in the quantity demanded. • Trips fall to 95, 000/hour. • Total expenditure rises to $209, 000/hour (= 95, 000 x $2. 20). • $209, 000 > $200, 000, the revenue from a $2. 00 toll.

Kesimpulan: Elastisitas dan Total Pengeluaran • Suatu peningkatan harga akan meningkatkan total pengeluaran, jika dan hanya jika, elastisitas harga dari permintaan adalah kurang dari 1, dalam nilai absolut (antara -1 dan nol) • Inelastic demand • Sedangkan penurunan harga akan meningkatkan total pengeluaran, jika dan hanya jika, elastisitas harga dari permintaan lebih besar dari 1, dalam nilai absolut (kurang dari -1) • Elastic demand

Elasticity and Total (Graph) • • At the point M, the demand curve is unit elastic. M is the midpoint of this linear demand curve Above M, demand is elastic, so total expenditure falls as the price rises Below M, demand is inelastic. so total expenditure falls as price falls. Total expenditure is maximized at the point M, where the elasticity = 1. Price Expenditure Elasticity > 1: Price reduction increases total expenditure; price increase reduces it. Elasticity = 1: Total expenditure is at a maximum M Elasticity < 1: Price reduction reduces total expenditure; price increases it. Quantity

Change in Expenditure Components • Old (price, quantity) is (P, Q). Price • New (price, quantity) is (P*, Q*). • Expenditures increase if G is bigger than E. • Since the point (P, Q) is above the midpoint of the linear demand curve, we know that total expenditures will increase at the lower price (P*, Q*). So, E must be smaller than G. P P* E F G Demand Q Q* Quantity

Own price elasticity and total revenue changes Total revenue (TR) is price times quantity. Along the demand curve P and Q move in opposite directions. Knowledge of Ed assists in knowing how TR will change.

Elasticity and total revenue relationship When we look at the collection of consumers in the market, at this time in our study we assume each consumer pays the same price per unit for the product. Also at this time in our study the total expenditure of the consumers in the market would equal the total revenue (TR) to the sellers. So, here we look at the whole demand side of the market in general.

Elasticity and total revenue relationship P P 1 Q 1 TR in the market is equal to the price in the market multiplied by the quantity traded in the market. In this diagram TR equals the area of the rectangle Q made by P 1, Q 1 and the horizontal and vertical axes. We know from math that the area of a rectangle is base times height and thus here that means P times Q.

Elasticity and total revenue relationship We will want to look at the change in values of a variable and in order to do so we want to have a consistent measure of change. In this regard let’s say the change in a variable is the later value minus the earlier value. Thus if the price should change from P 1 to P 2, then the change in price is P 2 - P 1, or similarly if the TR should change the change in TR is TR 2 - TR 1.

Elasticity and total revenue relationship P P 1 P 2 Now in this graph when the price is P 1 the TR = a + b(adding areas) and if the price is P 2 the TR = b + c. a b c The change in TR if the Q 1 Q 2 price should fall from P 1 to P 2 is (b + c) - (a + b) = c - a. Similarly, if the price should rise from P 2 to P 1 the change in TR is a - c. I will focus on price declines next. Q

Elasticity and total revenue relationship P P 1 P 2 a b c Q Since the change in TR is c - a, the value of the change will depend on whether c is bigger or smaller, or even equal to, a. In this diagram we see c > a and thus the change in TR > 0. Q 1 Q 2 This means that as the price falls, TR rises. I think you will recall that in the upper left of the demand is price elastic. Thus if the price falls in the elastic range of demand TR rises.

Elasticity and TR You will note on the previous screen that I had c - a. In the graph c is indicating the change in TR because we are selling more units. The area a is indicating the change in TR when there is a price change. We have to bring the two together to get the change in TR. Thus a lower price has a good and a bad. Good - sell more units. Bad - sell at lower price.

Elasticity and total revenue relationship P Now in this graph when the price is P 1 the TR = a + b(adding areas) and if the price is P 2 the TR = b P 1 + c. a P 2 c In this diagram we see c b Q < a and thus the change Q 1 Q 2 in TR < 0. I think you will recall that in the lower right of the demand is price inelastic. Thus if the price falls in the inelastic range of demand TR falls.

Elasticity and total revenue relationship P Now in this graph when the price is P 1 the TR = a + b(adding areas) and if P 1 a the price is P 2 the TR = b P 2 + c. b c In this diagram we see c Q = a and thus the change Q 1 Q 2 in TR = 0. I think you will recall that in the middle of the demand is unit elastic. Thus if the price falls in the unit elastic range of demand TR does not change.

Elasticity and TR P D Q TR Q When the price falls the quantity demanded always rises. As the quantity demanded rises (because of the price change) the TR is first rising in the elastic range, levels off when demand is unit elastic and TR falls in the inelastic range.

Hubungan Elastisitas Harga dengan Total Revenue (TR) P E>1 (elastis) E=1 (uniter) • TR = P x Q . • Misalnya digunakan persamaan permintaan linear; P = a – b. Q maka, • TR = (a-b. Q) x Q = a. Q –b. Q 2 Harga P P E>1 TR TR E=1 TR tetap E<1 (inelastis) 0 E<1 TR TR Q

Other Price Elasticities: Cross- Price Elasticity of Demand • Elasticity of demand with respect to the price of a complementary good (cross-price elasticity) • This elasticity is negative because as the price of a complementary good rises, the quantity demanded of the good itself falls. • Example (from last week) software is complementary with computers. When the price of software rises the quantity demanded of computers falls. • Cross-price elasticity quantifies this effect.

Other Price Elasticities: Cross Price Elasticity of Demand • Elasticity of demand with respect to the price of a substitute good (also a cross-price elasticity) • This elasticity is positive because as the price of a substitute good rises, the quantity demanded of the good itself rises. • Example (from last week) hockey is substitute for basketball. When the price of hockey tickets rises the quantity demanded of basketball tickets rises. • Cross-price elasticity quantifies this effect.

Elastisitas Silang • Kecenderungan perubahan permintaan suatu barang disebabkan terjadi perubahan harga barang lain. • Persamaan; • Elastisitas silang dapat menunjukkan hubungan 2 macam barang (komoditi) yang sifatnya; • Substitusi, dengan koefisien (+) • Komplementer, dengan koefisien (-) • Barang yang tidak saling berhubungan (netral)

Other Elasticities: Income Elasticity of Demand • The elasticity of demand with respect to a consumer’s income is called the income elasticity. • When the income elasticity of demand is positive (normal good), consumers increase their purchases of the good as their incomes rise (e. g. automobiles, clothing). • When the income elasticity of demand is greater than 1 (luxury good), consumers increase their purchases of the good more than proportionate to the income increase (e. g. ski vacations). • When the income elasticity of demand is negative (inferior good), consumers reduce their purchases of the good as their incomes rise (e. g. potatoes).

Elastisitas Pendapatan • Kecenderungan perubahan permintaan yang disebabkan oleh perubahan pendapatan masyarakat. • Persamaan; • Misalnya, jika penghasilan konsumen meningkat 10% permintaan barang X meningkat sebesar 15%. Koefisien elastisitas pendapatan terhadap permintaan barang X adalah • Barang Normal, EI positif • Barang Superior, EI positif • Barang Inferior, EI negatif

From Individual Supply to Market Supply • The supply of a good or service can be defined for an individual firm, or for a group of firms that make up a market or an industry. • Market supply is the sum of all the quantities of a good or service supplied period by all the firms selling in the market for that good or service.