Elastisitas

1. Elastisitas

2. MengukurElastisitas • Mengukurapakah? • Responsataureaksi • Apakahalasanuntukmengetahuinya? • ResponsterhadapPermintaandanPenawaranadalahsubstansi yang menjelaskanhal-halterkaitdengananalisispasar. • Mengapatidakmengacupada “slope” ataukemiringan? • Sebagaipembandingantarpasar : inter market • Sebagaipembandingdidalampasaritusendiri: intra market • “Slope” dapatmenimbulkankesalahpahaman • Suatu unit pengukuran yang bebas

3. Mengapa “Economists” menggunakanelastisitas • Elastisitasadalahsuatu unit pengukuran yang bebas. • Bukanlahsuatuhal yang material membandingkanduapasarmelaluihargadankuantitasdarisuatujenisbarangdenganmenggunakanelastisitas. • Elastisitasmemungkinkan “economists” untukmengkuantifikasiperbedaandiantarapasartanpamenstandarisasi unit daripengukuran.

4. Apakahelastisitas? • Mengukurpersentasedariperubahansatuvariabelsebagaihasildari 1 % perubahansatuvariabellainnya. • Terdiridariberbagaijeniselastisitas. • 4 jenis yang akandibahas. • 3 darifungsipermintaan • 1 darifungsipenawaran

5. 2 ElastisitasUtama • Elastisitashargadaripermintaan: kepekaanterhadapkuantitaspermintaansuatujenisbarangsebagaiakibatdariperubahanhargadaribarangtersebut. • Elastisitashargadaripenawaran: kepekaanterhadapkuantitaspenawaransuatujenisbarangsebagaiakibatdariperubahanhargadaribarangtersebut. • Keduanyaseringkalidimaknaisebagaielastisitasharga.

6. Contohdarielastisitashargadaripermintaan • Ketikaharga BBM meningkat 1%, kuantitaspermintaanterhadap BBM tersebutturun 0.2%, makapermintaanbensintidaksangatsensitifterhadapharga. • Elastisitashargadaripermintaanadalah-0.2 . • Ketikahargaperhiasanemasmeningkat 1%, kuantitaspermintaanterhadapperhiasanemastersebutturun 2.6%, makapermintaanperhiasanemassangatsensitifterhadapharga. • Elastisitashargadaripermintaanadalah-2.6 .

7. Contohdarielastisitashargadaripenawaran • KetikahargalukisanDaVincimeningkat 1%, kuantitaspenawaranterhadaplukisantersebuttidakberubah, makapenawaranlukisansepenuhnyatidaksensitifterhadapharga. • Elastisitashargadaripenawaranadalah0. • Ketikahargadagingmeningkat 1%, kuantitaspenawaranterhadapdagingtersebutmeningkat 5%, makapenawarandagingsangatsensitifterhadapharga. • Elastisitashargadaripenawaranadalah5.

8. Contohdari unit yang bebasdariperbandingan …1 • Bensindanperhiasan • Hal tersebutbukanlahsuatumasalahbahwabensindijualpergalonnya $1.09 danemasdijual per onsnya $290. • Kita membandingkanelastisitaspermintaandaribensin(-0.2)danperhiasanemas(-2.6). • Berdasarkanelastisitastersebutpermintaanperhiasanemasadalahlebihsensitifterhadapperubahanharga.

9. Contohdari unit yang bebasdariperbandingan …2 • Lukisandandaging • Hal tersebutbukanlahsuatumasalahbahwalukisanklasikdijualperunitnyajutaan dollar sementaradagingsapidijual per ponnyasekitar $1.50. • Kita membandingkanelastisitaspenawarandarilukisanklasik(0)dandagingsapi(5). • Berdasarkanelastisitastersebutpenawarandagingsapilebihsensitifterhadapperubahanharga.

10. Relasiekonomiinelastis • Suatuelastisitasadalahkeciljikanilainyaantara 0 dan 1 (dalamnilaiabsolut), kondisitersebutmenggambarkanrelasi yang inelastis. • Inelastispermintaanadalahkuantitaspermintaansuatujenisbarangsangattidaksensitifterhadapperubahanharga. • Inelastispenawaranadalahkuantitaspenawaransuatujenisbarangsangattidaksensitifterhadapperubahanharga.

11. Relasiekonomielastis • Suatuelastisitasadalahbesarjikanilainyalebihbesardari 1 (dalamnilaiabsolut), kondisitersebutmenggambarkanrelasi yang elastis. • Elastispermintaanadalahkuantitaspermintaansuatujenisbarangsensitifterhadapperubahanharga. • Elastispenawaranadalahkuantitaspenawaransuatujenisbarangsensitifterhadapperubahanharga.

12. 0 1 2 3 4 5 6 Size of Price Elasticities Unit elastic Inelastic Elastic • Unit elastic: own price elasticity equal to 1 • Inelastic: own price elasticity less than 1 • Elastic: own price elasticity greater than 1

13. 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

14. Catatan: • Elastisitashargadaripermintaanadalahselalunegatif. • Elastisitashargadaripermintaannilainyaabsolut (mengabaikantandanegatif). • Sehingga, meskipunhasilperhitungan formula menyebutkanbahwaelastisitashargadaripermintaanadalahnegatif, makaelastisitastersebutadalah 0.2 dalamcontohpertamadan 2.6 dalamcontohkedua.

15. Arc Formula untukElastisitas- Umum • Meskipun formula eksakuntukmenghitungsuatuelastisitasbergunasecarateori, dalamkenyatannya “economists” biasanyamengunakanpendekatanuntukmenghitungnya yang disebutarcelastisitas. • Elastisitasantaraduatitiksesungguhnyamerupakanpendekatan. • Diperlukanduatitikuntukmelakukanpenghitungan.

16. 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

17. 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

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

19. 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).

20. 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

21. 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

22. 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

23. ElastisitasPenawaran • Elastisitashargadaripenawaranadalahselalupositif. • Elastistashargadaripenawaranmerupakannilaisebenarnya.. • Cara yang samadigunakanuntukmenghitung formula titikdan arc padaelastisitaspenawaransebagaimanaelastisitaspermintaan.

24. BeberapaDefinisiTerkaitDenganNilaiEkstrimdariElastisitas • Economists menggunakanistilah “elastisitassempurna” dan “inelastissempurna” untukmenggambarkannilaiekstrimdarielastisitasharga. • Elastisitassempurnaberartibahwakuantitas (permintaanataupenawaran) sensitifterhadapharga. • Inelastissempurnaberartibahwakuantitas (permintaanataupenawaran) tidakmemilikisensitifitasterhadapharga.

25. Price Perfectly Elastic Demand (elasticity = ¥) Quantity 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.

26. Price Perfectly Inelastic Demand (elasticity = 0) 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.

27. Price Perfectly Elastic Supply (elasticity = ¥) 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.

28. Price Perfectly Inelastic Supply (elasticity = 0) 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.

29. 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.

30. 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

31. MenggunakanElastisitasPermintaan: Total Pengeluaran/Belanja • Total pengeluaranatassuatuprodukapakahnaikatauturunketikahargameningkat? • Harganaikberartilebihbanyakpengeluaranuntukmasing-masing unit. • Tetapi, kuantitaspermintaanturunsaatharganaik. • Sehingga, kitaharusmengukurelastisitashargadaripermintaanuntukmenjawabpermintaantersebut.

32. Contoh: TarifTolJembatan • Tariftoljembatan the George Washington adalah$2.00/trip. • Andaikankuantitaspermintaanadalah100,000 trips/hour. • Dan elastisitashargadaripermintaanuntukjembatantersebutadalah2.0, Berapakah total pengeluaranjikatariftoljembatantetapdanmeningkatsebesar 10%? Bandingkanhasilkeduanyasertaberikankesimpulan!!

33. 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.

34. ContohTarifTolJembatan, Bagian2 • Sekarangandaikanelastisitasdaripermintaanadalah0.5. • Bagaimanajumlahdariperjalanandanpengeluarantoldipengaruhiolehpeningkatan 10% tariftol?

35. 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.

36. Kesimpulan: Elastisitasdan Total Pengeluaran • Suatupeningkatanhargaakanmeningkatkan total pengeluaran, jikadanhanyajika, elastisitashargadaripermintaanadalahkurangdari 1, dalamnilaiabsolut (antara -1 dannol) • Inelastic demand • Sedangkanpenurunanhargaakanmeningkatkan total pengeluaran, jikadanhanyajika, elastisitashargadaripermintaanlebihbesardari 1, dalamnilaiabsolut (kurangdari -1) • Elastic demand

37. Elasticity and Total Expenditure (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. Elasticity > 1: Price reduction increases total expenditure; price increase reduces it. Price Elasticity = 1: Total expenditure is at a maximum Elasticity < 1: Price reduction reduces total expenditure; price increase increases it. M Quantity

38. Change in Expenditure Components • Old (price, quantity) is (P,Q). • 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. Price P E P* F G Demand Q Q* Quantity

39. 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.

40. 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.

41. Elasticity and total revenue relationship P 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 made by P1, Q1 and P1 Q Q1 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.

42. 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 P1 to P2, then the change in price is P2 - P1, or similarly if the TR should change the change in TR is TR2 - TR1.

43. Elasticity and total revenue relationship P Now in this graph when the price is P1 the TR = a + b(adding areas) and if the price is P2 the TR = b + c. The change in TR if the price should fall P1 P2 a b c Q Q1 Q2 from P1 to P2 is (b + c) - (a + b) = c - a. Similarly, if the price should rise from P2 to P1 the change in TR is a - c. I will focus on price declines next.

44. Elasticity and total revenue relationship P 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. P1 P2 a b c Q Q1 Q2 This means that as the price falls, TR rises. I think you will recall that in the upper left of the demand the demand is price elastic. Thus if the price falls in the elastic range of demand TR rises.

45. 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.

46. Elasticity and total revenue relationship P Now in this graph when the price is P1 the TR = a + b(adding areas) and if the price is P2 the TR = b + c. In this diagram we see c < a and thus the change in TR < 0. P1 P2 a b c Q Q1 Q2 I think you will recall that in the lower right of the demand the demand is price inelastic. Thus if the price falls in the inelastic range of demand TR falls.

47. Elasticity and total revenue relationship P Now in this graph when the price is P1 the TR = a + b(adding areas) and if the price is P2 the TR = b + c. In this diagram we see c = a and thus the change in TR = 0. P1 P2 a b c Q Q1 Q2 I think you will recall that in the middle of the demand the demand is unit elastic. Thus if the price falls in the unit elastic range of demand TR does not change.

48. Elasticity and TR P 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. D Q TR Q

49. HubunganElastisitasHargadenganTotal Revenue (TR) P E>1 (elastis) • TR = P x Q • Misalnya digunakan persamaan permintaan linear; P = a – bQ maka, • TR = (a-bQ) x Q = aQ –bQ2 . E=1 (uniter) E<1 (inelastis) 0 Q

50. 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.