ILMU EKONOMI MIKRO (MIKROEKONOMI)
• Ilmu ekonomi mikro (sering juga ditulis
mikroekonomi) adalah cabang dari ilmu
ekonomi yang mempelajari perilaku
konsumen dan perusahaan serta
penentuan harga-harga pasar dan
kuantitas faktor input, barang, dan jasa
yang diperjualbelikan.
ILMU EKONOMI MIKRO (MIKROEKONOMI)
• Ekonomi mikro meneliti bagaimana berbagai
keputusan dan perilaku tersebut mempengaruhi
penawaran dan permintaan atas barang dan
jasa, yang akan menentukan harga; dan
bagaimana harga, pada gilirannya, menentukan
penawaran dan permintaan barang dan jasa
selanjutnya. Individu yang melakukan kombinasi
konsumsi atau produksi secara optimal,
bersama-sama individu lainnya di pasar, akan
membentuk suatu keseimbangan dalam skala
makro; dengan asumsi bahwa semua hal lain
tetap sama (ceteris paribus).
ILMU EKONOMI MIKRO (MIKROEKONOMI)
• Kebalikan dari ekonomi mikro ialah
ekonomi makro, yang membahas aktivitas
ekonomi secara keseluruhan, terutama
mengenai pertumbuhan ekonomi, inflasi,
pengangguran, berbagai kebijakan
perekonomian yang berhubungan, serta
dampak atas beragam tindakan
pemerintah (misalnya perubahan tingkat
pajak) terhadap hal-hal tersebut.
Tinjauan umum
• Salah satu tujuan ekonomi mikro adalah menganalisa
pasar beserta mekanismenya yang membentuk harga
relatif kepada produk dan jasa, dan alokasi dari sumber
terbatas diantara banyak penggunaan alternatif.
Ekonomi mikro menganalisa kegagalan pasar, yaitu
ketika pasar gagal dalam memproduksi hasil yang
efisien; serta menjelaskan berbagai kondisi teoritis yang
dibutuhkan bagi suatu pasar persaingan sempurna.
Bidang-bidang penelitian yang penting dalam ekonomi
mikro, meliputi pembahasan mengenai keseimbangan
umum (general equilibrium), keadaan pasar dalam
informasi asimetris, pilihan dalam situasi ketidakpastian,
serta berbagai aplikasi ekonomi dari teori permainan.
Juga mendapat perhatian ialah pembahasan mengenai
elastisitas produk dalam sistem pasar.
Asumsi dan definisi
• Teori penawaran dan permintaan biasanya
mengasumsikan bahwa pasar merupakan pasar
persaingan sempurna. Implikasinya ialah terdapat
banyak pembeli dan penjual di dalam pasar, dan tidak
satupun diantara mereka memiliki kapasitas untuk
mempengaruhi harga barang dan jasa secara signifikan.
Dalam berbagai transaksi di kehidupan nyata, asumsi ini
ternyata gagal, karena beberapa individu (baik pembeli
maupun penjual) memiliki kemampuan untuk
mempengaruhi harga. Seringkali, dibutuhkan analisa
yang lebih mendalam untuk memahami persamaan
penawaran-permintaan terhadap suatu barang.
Bagaimanapun, teori ini bekerja dengan baik dalam
situasi yang sederhana.
Model operasi
 Sebuah perusahaan dikatakan membuat
sebuah keuntungan ekonomi ketika
average total cost lebih rendah dari setiap
produk
tambahan
pada
keluaran
maksimalisasi keuntungan. Keuntungan
ekonomi adalah setara dengan kuantitas
keluaran dikali dengan perbedaan antara
average total cost dan harga.
Model operasi
 Sebuah perusahaan dikatakan membuat
sebuah
keuntungan
normal
ketika
keuntungan ekonominya sama dengan
nol. Keadaan ini terjadi ketika average
total cost setara dengan harga pada
keluaran maksimalisasi keuntungan.
Model operasi
 Jika harga adalah di antara average total cost
dan average variable cost pada keluaran
maksimalisasi keuntungan, maka perusahaan
tersebut dalam kondisi kerugian minimal.
Perusahaan ini harusnya masih meneruskan
produksi, karena kerugiannya akan makin
membesar jika berhenti produksi. Dengan
produksi terus menerus, perusahaan bisa
menaikkan biaya variabel dan akhirnya biaya
tetap, tetapi dengan menghentikan semuanya
akan mengakibatkan kehilangan semua biaya
tetapnya.
Model operasi
• Jika harga dibawah average variable cost pada
maksimalisasi keuntungan, perusahaan harus
melakukan penghentian. Kerugian diminimalisir dengan
tidak memproduksi sama sekali, karena produksi tidak
akan menghasilkan keuntungan yang cukup signifikan
untuk membiayai semua biaya tetap dan bagian dari
biaya variabel. Dengan tidak berproduksi, kerugian
perusahaan hanya pada biaya tetap. Dengan kehilangan
biaya tetapnya, perusahaan menemui tantangan. Akan
keluar dari pasar seutuhnya atau tetap bersaing dengan
resiko kerugian menyeluruh
Kegagalan pasar
• Dalam ekonomi mikro, istilah "kegagalan pasar" tidak
berarti bahwa sebuah pasar tidak lagi berfungsi.
Malahan, sebuah kegagalan pasar adalah situasi
dimana sebuah pasar efisien dalam mengatur produksi
atau alokasi barang dan jasa ke konsumen. Ekonom
normalnya memakai istilah ini pada situasi dimana
inefisiensi sudah dramatis, atau ketika disugestikan
bahwa institusi non pasar akan memberi hasil yang
diinginkan. Di sisi lain, pada konteks politik, pemegang
modal atau saham menggunakan istilah kegagalan
pasar untuk situasi saat pasar dipaksa untuk tidak
melayani "kepentingan publik", sebuah pernyataan
subyektif yang biasanya dibuat dari landasan moral atau
sosial.
Empat jenis utama penyebab
kegagalan pasar adalah:
 Monopoli atau dalam kasus lain dari
penyalahgunaan dari kekuasaan pasar
dimana "sebuah" pembeli atau penjual
bisa memberi pengaruh signifikan pada
harga atau keluaran. Penyalahgunaan
kekuasaan pasar bisa dikurangi dnegan
menggunakan undang-undang anti trust.
Empat jenis utama penyebab
kegagalan pasar adalah:
 Eksternalitas, dimana terjadi dalam kasus dimana "pasar
tidak dibawa kedalam akun dari akibat aktifitas ekonomi
didalam orang luar/asing." Ada eksternalitas positif dan
eksternalitas negatif. Eksternalitas positif terjadi dalam
kasus seperti dimana program kesehatan keluarga di
televisi meningkatkan kesehatan publik. Eksternalitas
negatif terjadi ketika proses dalam perusahaan
menimbulkan polusi udara atau saluran air. Eksternalitas
negatif bisa dikurangi dengan regulasi dari pemerintah,
pajak, atau subsidi, atau dengan menggunakan hak
properti untuk memaksa perusahaan atau perorangan
untuk menerima akibat dari usaha ekonomi mereka pada
taraf yang seharusnya.
Empat jenis utama penyebab
kegagalan pasar adalah:
 Barang publik seperti pertahanan nasional dan kegiatan
dalam kesehatan publik seperti pembasmian sarang
nyamuk. Contohnya, jika membasmi sarang nyamuk
diserahkan pada pasar pribadi, maka jauh lebih sedikit
sarang yang mungkin akan dibasmi. Untuk menyediakan
penawaran yang baik dari barang publik, negara
biasanya
menggunakan
pajak-pajak
yang
mengharuskan semua penduduk untuk membayar pda
barang publik tersebut (berkaitan dengan pengetahuan
kurang
dari
eksternalitas
positif
pada
pihak
ketiga/kesejahteraan sosial).
Empat jenis utama penyebab
kegagalan pasar adalah:
• Kasus dimana terdapat informasi asimetris
atau ketidak pastian (informasi yang
inefisien). Informasi asimetris terjadi ketika
salah satu pihak dari transaksi memiliki
informasi yang lebih banyak dan baik dari
pihak yang lain. Biasanya para penjua
yang lebih tahu tentang produk tersebut
daripada sang pembeli, tapi ini tidak selalu
terjadi dalam kasus ini.
Biaya peluang
• Walaupun biaya peluang (opportunity cost)
terkadang sulit untuk dihitung, efek dari biaya
peluang sangatlah universal dan nyata pada
tingkat perorangan. Bahkan, prinsip ini dapat
diaplikasikan kepada semua keputusan, dan
bukan hanya bidang ekonomi. Sejak
kemunculannya dalam karya seorang ekonom
Jerman bernama Freidrich von Wieser,
sekarang biaya peluang dilihat sebagai dasar
dari teori nilai marjinal
Biaya peluang
• Biaya peluang merupakan salah satu cara
untuk melakukan perhitungan dari sesuatu
biaya. Bukan saja untuk mengenali dan
menambahkan biaya ke proyek, tetapi
juga mengenali cara alternatif lainnya
untuk menghabiskan suatu jumlah uang
yang sama. Keuntungan yang akan hilang
sebagai akibat dari alternatif terbaik
lainnya; adalah merupakan biaya peluang
dari pilihan pertama.
Supply and demand
• Supply and demand is an economic
model based on price and quantity in a
market. It predicts that in a competitive
market, price will function to equalize the
quantity demanded by consumers, and the
quantity supplied by producers, resulting in
an economic equilibrium of price and
quantity. The model incorporates other
factors changing equilibrium as a shift of
demand and/or supply.
Supply and demand
Supply and demand
• Supply and demand is an economic
model based on price and quantity in a
market. It predicts that in a competitive
market, price will function to equalize the
quantity demanded by consumers, and the
quantity supplied by producers, resulting in
an economic equilibrium of price and
quantity. The model incorporates other
factors changing equilibrium as a shift of
demand and/or supply.
Supply schedule
• The supply schedule, graphically represented by
the supply curve, is most often expressed by the
relationship between market price and amount
of goods produced. In short-run analysis, where
some input variables are fixed, a positive slope
can reflect the law of diminishing marginal
returns, which states that beyond some level of
output, additional units of output require larger
amounts of input. In the long-run, where no input
variables are fixed, a positively-sloped supply
curve can reflect diseconomies of scale.
Supply curve shifts
Demand schedule
Elasticity
• Elasticity is a central concept in the theory of
supply and demand. In this context, elasticity
refers to how supply and demand respond to
various factors. One way to define elasticity is
the percentage change in one variable divided
by the percentage change in another variable
(known as arc elasticity, which calculates the
elasticity over a range of values, in contrast with
point elasticity, which uses differential calculus
to determine the elasticity at a specific point). It
is a measure of relative changes.
Elasticity
• In economics, elasticity is the ratio of the
percent change in one variable to the
percent change in another variable. It is a
tool for measuring the responsiveness of a
function to changes in parameters in a
relative way. Commonly analyzed are
elasticity of substitution, price and wealth.
Elasticity is a popular tool among
empiricists because it is independent of
units and thus simplifies data analysis
The demand curve (D1) is perfectly
("infinitely") elastic
The demand curve (D2) is perfectly
inelastic.
Unit elasticity for a supply line
passing through the origin
Vertical supply curve (Perfectly
Inelastic Supply)
Elastisitas permintaan
• Dalam ilmu ekonomi, elastisitas permintaan
atau price elasticity of demand (PED) adalah
ukuran kepekaan perubahan jumlah permintaan
barang terhadap perubahan harga.
• Elastisitas permintaan mengukur seberapa
besar kepekaan perubahan jumlah permintaan
barang terhadap perubahan harga. Ketika harga
sebuah barang turun, jumlah permintaan
terhadap barang tersebut biasanya naik —
semakin rendah harganya, semakin banyak
benda itu dibeli.
Elastisitas permintaan
• Elastisitas permintaan ditunjukan dengan
rasio persen perubahan jumlah
permintaan dan persen perubahan harga.
Ketika elastisitas permintaan suatu barang
menunjukkan nilai lebih dari 1, maka
permintaan terhadap barang tersebut
dikatakan elastis di mana besarnya jumlah
barang yang diminta sangat dipengaruhi
oleh besar-kecilnya harga
Elastisitas permintaan
• Sementara itu, barang dengan nilai elastisitas kurang
dari 1 disebut barang inelastis, yang berarti pengaruh
besar-kecilnya harga terhadap jumlah-permintaan tidak
terlalu besar.
• Sebagai contoh, jika harga sepeda motor turun 10% dan
jumlah permintaan atas sepeda motor itu naik 20%,
maka nilai elastisitas permintaannya adalah 2; dan
barang tersebut dikelompokan sebagai barang elastis
karena nilai elastisitasnya lebih dari 1. Perhatikan bahwa
penurunan harga sebesar 1% menyebabkan
peningkatan jumlah permintaan sebesar 2%, dengan
demikian dapat dikatakan bahwa jumlah permintaan atas
sepeda motor sangat dipengaruhi oleh besarnya harga
yang ditawarkan.
Elastisitas permintaan
koefesien
Elastisitas
n=0
Inelastis sempurna
0<n<1
Inelastis
n=1
Elastis uniter
1<n<∞
Elastis
n=∞
Elastis sempurna
Price elasticity of demand
• Price elasticity of demand is defined as the
measure of responsiveness in the quantity
demanded for a commodity as a result of
change in price of the same commodity. In other
words, it is percentage change in quantity
demanded as per the percentage change in
price of the same commodity. In economics and
business studies, the price elasticity of
demand (PED) is a measure of the sensitivity of
quantity demanded to changes in price.
elasticity of demand
• It is measured as elasticity, that is it
measures the relationship as the ratio of
percentage changes between quantity
demanded of a good and changes in its
price. In simpler words, demand for a
product can be said to be very inelastic if
consumers will pay almost any price for
the product, and very elastic if consumers
will only pay a certain price, or a narrow
range of prices, for the product.
elasticity of demand
• Inelastic demand means a producer can
raise prices without much hurting demand
for its product, and elastic demand means
that consumers are sensitive to the price
at which a product is sold and will not buy
it if the price rises by what they consider
too much
Perfectly Inelastic Demand
Perfectly Elastic Demand
elasticity of demand
Value
Meaning
n=0
Perfectly inelastic.
0 > n > -1
Relatively inelastic.
n = -1
Unit (or unitary) elastic.
-1 > n > -∞
Relatively elastic.
n = -∞
Perfectly elastic.
elasticity of demand
• A price drop usually results in an increase in the quantity
demanded by consumers (see Giffen good for an
exception). The demand for a good is relatively
inelastic when the change in quantity demanded is less
than change in price. Goods and services for which no
substitutes exist are generally inelastic. Demand for an
antibiotic, for example, becomes highly inelastic when it
alone can kill an infection resistant to all other antibiotics.
Rather than die of an infection, patients will generally be
willing to pay whatever is necessary to acquire enough
of the antibiotic to kill the infection.
elasticity of demand
• When the price elasticity of demand for a good is
unit elastic (or unitary elastic) (|Ed| = 1), the
percentage change in quantity is equal to that in
price
• When the price elasticity of demand for a good is
perfectly elastic (Ed is undefined), any
increase in the price, no matter how small, will
cause demand for the good to drop to zero.
Hence, when the price is raised, the total
revenue of producers falls to zero. The demand
curve is a horizontal straight line
Elasticity and revenue
•
A set of graphs shows the relationship between demand and total revenue. As price
decreases in the elastic range, revenue increases, but in the inelastic range, revenue
decreases
elasticity of demand
• When the price elasticity of demand for a goods
is inelastic (|Ed| < 1), the percentage change in
quantity demanded is smaller than that in price.
Hence, when the price is raised, the total
revenue of producers rises, and vice versa.
• When the price elasticity of demand for a good is
elastic (|Ed| > 1), the percentage change in
quantity demanded is greater than that in price.
Hence, when the price is raised, the total
revenue of producers falls, and vice versa
elasticity of demand
• When the price elasticity of demand for a good is
unit elastic (or unitary elastic) (|Ed| = 1), the
percentage change in quantity is equal to that in
price
• When the price elasticity of demand for a good is
perfectly elastic (Ed is undefined), any
increase in the price, no matter how small, will
cause demand for the good to drop to zero.
Hence, when the price is raised, the total
revenue of producers falls to zero. The demand
curve is a horizontal straight line
elasticity of demand
• When the price elasticity of demand for a good is
perfectly inelastic (Ed = 0), changes in the price do not
affect the quantity demanded for the good. The demand
curve is a vertical straight line; this violates the law of
demand. An example of a perfectly inelastic good is a
human heart for someone who needs a transplant;
neither increases nor decreases in price affect the
quantity demanded (no matter what the price, a person
will pay for one heart but only one; nobody would buy
more than the exact amount of hearts demanded, no
matter how low the price is).
Mathematical definition
•
The formula used to calculate the coefficient of price elasticity of demand for a
given product is
Mathematical definition
• using the differential calculus form:
Point-price elasticity
• Point Elasticity = (% change in Quantity) /
(% change in Price)
• Point Elasticity = (∆Q/Q)/(∆P/P)
• Point Elasticity = (P ∆Q) / (Q ∆P)
• Point Elasticity = (P/Q)(∆Q/∆P) Note: In
the limit (or "at the margin"), "(∆Q/∆P)" is
the derivative of the demand function with
respect to P. "Q" means 'Quantity' and "P"
means 'Price'.
Point-price elasticity
•
Example
Suppose a certain good (say, laserjet printers) has a demand curve Q = 1,000 0.6P. We wish to determine the point-price elasticity of demand at P = 80 and P
= 40. First, we take the derivative of the demand function Q with respect to P:
Point-price elasticity
•
•
Next we apply the equation for point-price elasticity
to the ordered pairs (40, 976) and (80, 952). We have
at P=40, point-price elasticity e = -0.6(40/976) = -0.02.
at P=80, point-price elasticity e = -0.6(80/952) = -0.05.
Aggregate demand
• In economics, aggregate demand is the total demand
for final goods and services in the economy (Y) at a
given time and price level[1]. It is the amount of goods
and services in the economy that will be purchased at all
possible price levels. [2]This is the demand for the gross
domestic product of a country when inventory levels are
static. It is often called effective demand or abbreviated
as 'AD'. In a general aggregate supply-demand chart,
the aggregate demand curve (AD) slopes downward
(indicating that higher outputs are demanded at lower
price levels).
Aggregate demand
•
An aggregate demand curve is the sum of individual demand curves for different
sectors of the economy. The aggregate demand is usually described as a linear sum
of four separable demand sources
is consumption = ac + bc*(Y - T),
is Investment,
is Government spending,
is Net export,
is total exports, and
is total imports = am + bm*(Y - T),.
Aggregate demand
• Keynesian Cross
Aggregate demand
• In the "Keynesian cross diagram," a desired total
spending (or aggregate expenditure, or "aggregate
demand") curve (shown in blue) is drawn as a rising line
since consumers will have a larger demand with a rise in
disposable income, which increases with total national
output. This increase is due to the positive relationship
between consumption and consumers' disposable
income in the consumption function. Aggregate demand
may also rise due to increases in investment (due to the
accelerator effect), while this rise is reduced if imports
and tax revenues rise with income. Equilibrium in this
diagram occurs where total demand, AD, equals the total
amount of national output, Y, (which corresponds to total
national income or production). Here, total demand
equals total supply.
Aggregate supply
Aggregate supply
Aggregate supply
• In economics, aggregate supply is the
total supply of goods and services
produced by a national economy during a
specific time period. It is the the total
amount of goods and services in the
economy available at all possible price
levels
Aggregate supply
• 1. Sometimes the "Z curve" in the "Keynesian cross" diagram is
referred to as "aggregate supply." This curve often represents the
total amount of production that corresponds to the total amount of
income in a country during a specific time period. Because the sum
of all income received corresponds to the sum of all production, this
is drawn as a 45 degree line. In this diagram, the desired total
spending line crosses this Z curve, determining the equilibrium level
of production, income, and spending.sap
• 2. In neo-Keynesian theory seen in many textbooks, an "aggregate
supply and demand" diagram is drawn that looks like a typical
Marshallian supply and demand diagram. The aggregate supply
(AS) curve is usually drawn as upward-sloping in the short run, since
Aggregate Demand-Aggregate
Supply model
Price elasticity of supply
•
In economics, the price elasticity of supply is defined as a numerical
measure of the responsiveness of the quantity supplied of product (A) to a
change in price of product (A) alone.
Income elasticity of demand
(YED)
• In economics, the income elasticity of demand
measures the responsiveness of the quantity
demanded of a good to the change in the
income of the people demanding the good. It is
calculated as the ratio of the percent change in
quantity demanded to the percent change in
income. For example, if, in response to a 10%
increase in income, the quantity of a good
demanded increased by 20%, the income
elasticity of demand would be 20%/10% = 2.
Income elasticity of demand
(YED
• Inferior good's demand falls as consumer
income increases
Income elasticity of demand
(YED )
• A negative income elasticity of demand is associated
with inferior goods; an increase in income will lead to a
fall in the quantity demanded and may lead to changes
to more luxurious substitutes.
• A positive income elasticity of demand is associated
with normal goods; an increase in income will lead to a
rise in the quantity demanded. If income elasticity of
demand of a commodity is less than 1, it is a necessity
good. If the elasticity of demand is greater than 1, it is a
luxury good or a superior good
• A zero income elasticity (or inelastic) demand occurs
when an increase in income is not associated with a
change in the quantity demanded of a good. These
would be sticky goods.
Mathematical definition
or alternatively:
This can be rewritten in the form:
With income I, and vector of prices . Many necessities have an income
elasticity of demand
between zero and one: expenditure on these goods
W
may increasei with income, but not as fast as income does, so the
proportion of texpenditure on these goods falls as income rises. This
observation for
h food is known as Engel's law.
i
n
c
o
Cross elasticity of demand
• In economics, the cross elasticity of demand and
cross price elasticity of demand measures the
responsiveness of the quantity demanded of a good to a
change in the price of another good.
• It is measured as the percentage change in quantity
demanded for the first good that occurs in response to a
percentage change in price of the second good. For
example, if, in response to a 10% increase in the price of
fuel, the quantity of new cars that are fuel inefficient
demanded decreased by 20%, the cross elasticity of
demand would be -20%/10% = -2.
Cross elasticity of demand
• The formula used to calculate the
coefficient cross elasticity of demand is
or:
Cross elasticity of demand
Two goods that complement each other show a negative cross elasticity of
demand: as the price of good Y rises, the demand for good X falls
In the example above, the two goods, fuel and cars(consists of fuel
consumption), are complements - that is, one is used with the other. In
these cases the cross elasticity of demand will be negative. In the case of
perfect complements, the cross elasticity of demand is infinitely negative.
Cross elasticity of demand
• Where the two goods are substitutes the cross elasticity of demand
will be positive, so that as the price of one goes up the quantity
demanded of the other will increase. For example, in response to an
increase in the price of carbonated soft drinks, the demand for noncarbonated soft drinks will rise. In the case of perfect substitutes, the
cross elasticity of demand is equal to infinity.
• Where the two goods are complements the cross elasticity of
demand will be negative, so that as the price of one goes up the
quantity demanded of the other will decrease. For example, in
response to an increase in the price of fuel, the demand for new
cars will decrease.
• Where the two goods are independent, the cross elasticity demand
will be zero: as the price of one good changes, there will be no
change in quantity demanded of the other good.