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From short-run average cost curves to long-run average cost curves

This graph shows a long run average cost as a sum of minimum short run average costs.
The five different short-run average cost (SRAC) curves each represents a different level of fixed costs, from the low level of fixed costs at SRAC 1 to the high level of fixed costs at SRAC 5 . Other SRAC curves, not shown in the diagram, lie between the ones that are shown here. The long-run average cost (LRAC) curve shows the lowest cost for producing each quantity of output when fixed costs can vary, and so it is formed by the bottom edge of the family of SRAC curves. If a firm wished to produce quantity Q 3 , it would choose the fixed costs associated with SRAC 3 .

The long-run average cost curve shows the cost of producing each quantity in the long run, when the firm can choose its level of fixed costs and thus choose which short-run average costs it desires. If the firm plans to produce in the long run at an output of Q 3 , it should make the set of investments that will lead it to locate on SRAC 3 , which allows producing q 3 at the lowest cost. A firm that intends to produce Q 3 would be foolish to choose the level of fixed costs at SRAC 2 or SRAC 4 . At SRAC 2 the level of fixed costs is too low for producing Q 3 at lowest possible cost, and producing q 3 would require adding a very high level of variable costs and make the average cost very high. At SRAC 4 , the level of fixed costs is too high for producing q 3 at lowest possible cost, and again average costs would be very high as a result.

The shape of the long-run cost curve, as drawn in [link] , is fairly common for many industries. The left-hand portion of the long-run average cost curve, where it is downward- sloping from output levels Q 1 to Q 2 to Q 3 , illustrates the case of economies of scale. In this portion of the long-run average cost curve, larger scale leads to lower average costs. This pattern was illustrated earlier in [link] .

In the middle portion of the long-run average cost curve, the flat portion of the curve around Q 3 , economies of scale have been exhausted. In this situation, allowing all inputs to expand does not much change the average cost of production, and it is called constant returns to scale    . In this range of the LRAC curve, the average cost of production does not change much as scale rises or falls. The following Clear it Up feature explains where diminishing marginal returns fit into this analysis.

How do economies of scale compare to diminishing marginal returns?

The concept of economies of scale, where average costs decline as production expands, might seem to conflict with the idea of diminishing marginal returns, where marginal costs rise as production expands. But diminishing marginal returns refers only to the short-run average cost curve, where one variable input (like labor) is increasing, but other inputs (like capital) are fixed. Economies of scale refers to the long-run average cost curve where all inputs are being allowed to increase together. Thus, it is quite possible and common to have an industry that has both diminishing marginal returns when only one input is allowed to change, and at the same time has increasing or constant economies of scale when all inputs change together to produce a larger-scale operation.

Questions & Answers

how environment affect demand and supply of commodity ?
Amos Reply
Wht at the criteria for market ?
what is difference between monitory policy and fiscal policy?
Malik Reply
monetary policy is a policy thrust by National Govt(CBN) to influence government spending, purchase &taxes
necessity of economics
Pamela Reply
I will say want,choice,opportunity cost,scarcity,scale of preference
what is monopoly market.How price output are determined under monopoly market
b) Monopoly market is an impecfect market where s single firm having the innovation to produce a particular commodity.Prices are determined through output since there are no other competitive.
Monopoly market:firm has market power & does not respond to market price
Explain the process of price determination under perfect competition market with suitable diagram
bisham Reply
Price determination under perfect competition via this process :firms have no market power to influence price rather firms respond to market price.
price is different from demand- demand is amount of commodity
Effah Reply
demand is amount /quantity of commodity a potential buyer is willing to buy at a given price at market
demand is a desire of customer on commodity with the ability to pay it and willing to buy it at given price of commodity
demand is price of what
Faith Reply
show that shortrun average cost
Baby Reply
what is economics
Mbah Reply
what is money
what is money
Difine macro economics
money is a medium of exchange between goods and services,maybe inform of currency.
Economics is study of how human beings strive to satisfy numerous wants using limited available resources.
how do you find the maximum number of workers the firms should employ order to produce where there are increasing returns
what are implications of computing national income?.
what is the formulae for calculating national income
it calculated by value added method
classify the production units like agriculture, banking, transport etc
money is anything that is generally acceptetable for human
Estimate the net value added(NVA) at fixed cost by each industrial structure
definition of unemployment
Adam Reply
what are the causes of unemployment?
Mbubi Reply
The main causes of unemployment are listed below. 1. Frictional unemployment 2. Cyclical unemployment 3. Structural unemployment
We can also categorize the causes on a broader sense as: 1. Political and 2. Social cause As unemployeement root causes are embaded in this two.
would opportunity cost exist if there was no scarcity?
yes just because the opportunity cost arose when there is Alternative to choose among the alternatives.
I am thinking that, if our resources were unlimited, then there wouldn't be any need to forgo some wants. Hence the inexistence if opportunity cost
politics has done what?
consider time assani
I'm Emmanuel,...I taught the main cause is the change in gov't.
...Lack of capital to set up a firm respectively
I would like to bring in Educational levels can also be the cause the cause of the problem respectively
lack of skills among the new generation is the serious issue.
Where I come from , I don't see why education or personal aspects seem to do with unimployment, technically the motivation and eigerness in all works of live is there , dispite the cultural influence and physical bearriors;the thing we lacking is Government Support and open market ethics.
sorry about that-(repation). We have a over powering ethical political system that's displacing the marketing asspects of economy and causing large scale unemployment right across the board...
can someone Explain Expansionary Monetary Policy and Contractionary Monetary Policy Using one of the instrument of Monetary Policy? Please am kinda lost here?. ta
Emmanuel Reply
using a graph show the case of substitute and compliment goods
Ade Reply
can anyone give me a simple explanation to Five Sector Macroeconomics?
Can someone please define what economics is
jason Reply
economics simply is a social science subject that study human behavior.
economics is a social science which studies human behaviour as a relationship between ends and scarce means that has alternative uses
Can someone please tell me how to calculate GDP
emmanual kapal to calculate GDP (Gross Domestic Product) has three method in calculating it (1)income approach (2) expenditure approach (3) value added method
thanks Alae
u are welcome
in basic terms economics is revered to as battery system, it date back to when Men sees the need to exchange sapless goods and produce to gain , either wealth , basic necessities or to establish trading ties for personal benefit or social asspects in terms of coexistence and continuity, future .
what is the law of demand
Berlinda Reply
keep other thing constant, when the price increases demand decrease when the price decreases demand increases of the commodity.
all things being equal,quantity demanded decrease as price increase and increase as price decrease
there's practial joke to it ..." the higher the demand ; scarcity, increase in production and drop in quality"... quite the controversy - for example China vs Europe, United States and we are all boxed up in between somewhere...
Other thing remain constant the low price of commodity the high quantity of commodity and vice versa is true
Explain Effective demand
Anita Reply
What is effective demand
like Modi is in demand...best example of effective demand
Don't get you
Anita you mean you don't get me or who?
level of demand that represents a real intention to purchase by people with the means to pay

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Source:  OpenStax, Principles of economics. OpenStax CNX. Sep 19, 2014 Download for free at http://legacy.cnx.org/content/col11613/1.11
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