Front Page Titles (by Subject) CHAPTER 7: PRINCIPLES OF PRICE - Economics, vol. 1: Economic Principles
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CHAPTER 7: PRINCIPLES OF PRICE - Frank A. Fetter, Economics, vol. 1: Economic Principles 
Economics, vol. 1: Economic Principles, (New York: The Century Co., 1915).
Part of: Economics, 2 vols.
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PRINCIPLES OF PRICE
§ 1. Buyers’ composite valuation curve. § 2. Sellers’ composite valuation curve. § 3. Price the resultant of demand and supply. § 4. The market as a two-sided auction. § 5. Supply and demand coördinate in price-determination. § 6. Price in a permanent market. § 7. Effect of the market upon valuations. § 8. The point of price-adjustment. § 9. Social factors in individual valuations. § 10. Objective conditions to be studied.
§ 1. Buyers’ composite valuation curve. We have now to examine the process by which market-price is determined where two groups of bidders are present. This fulfils the conditions of a complete market, where there is two-sided, competitive bidding. Each trader comes to the market with valuations already in his mind more or less definitely. It may be that he is disposed to buy one unit if the price is high;1 if it is lower he will buy two units; if still lower, three units, etc. Or he is disposed to sell one unit at a certain price, two units if the price offered is higher, three if it is still higher, etc. The situation from the standpoint of the prospective buyers is represented in Figure 9. One of them (B 1) stands ready to purchase one unit at a price as high as 14 if he can do no better, but he will, of course, buy at a lower figure if possible. B 2 will, if he must, pay as high as 13 for a unit. Other buyers2 are willing to buy (one unit each) at prices respectively lower—12, 11, etc. At the extreme end of the scale there are certain individuals who would be induced to buy only by a price extremely low—4, 3, 1, etc. The diagram, therefore, represents this situation where the individual (prospective) buyers have different mental attitudes (valuations) as regards the good in question, and where in the aggregate the whole body of buyers stand ready to take the various amounts indicated, according as the prevailing price is higher or lower. If it is high they will take a relatively small quantity: if it is low they will take a larger amount. If, for example, the price should prove to be 12, it will be seen that only four units will be taken by the would-be purchasers. They will be secured, of course, by the most urgent buyers, B 1, B 2, B 3, and B 4. There is no one else who stands ready to buy at a price as high as 12. There are others who would buy at a lower figure, but if the ruling market price is as high as 12 they are, by their own attitude of choice, necessarily excluded from the actual market transactions. Similarly for any other price in the scale there will be a definite number of included or actual buyers, and a definite amount of the good which in the aggregate will be taken by those buyers at that price. This amount, the demand, which the buyers will take at any specified price is a composite, the combined result, of course, of the bids of the various individuals concerned.
§ 2. Sellers’ composite valuation curve. We may show in a similar way by Figure 10 the conditions of supply. S 1, the most urgent seller, is willing to sell one unit at a price as low as 4;3 S 7 will part with a unit at a price of 7.5 if he can do no better; S 12 will not be tempted to sell unless he can get 10 for a unit of the good, etc. Here again the diagram simply depicts the fact that at any given price there will be a certain number of actual or included sellers, and the amount offered by those sellers at that price, or the supply, will also be a definite quantity. At a low price this quantity is small; at a high price it is large.
§ 3. Price the resultant of demand and supply. Our question now is what is the market-price which naturally emerges from the demand- and supply-conditions which we have been considering. If one of these curves be superimposed upon the other, they are seen to cross at the point corresponding to ten units of sale-goods, and to the price of nine per unit. All that the diagram means is that under the supposed conditions of demand and supply (i.e., ten units offered by the sellers, and ten asked by the buyers at the same price, 9), the market-price which actually prevails will be the price (9) at which the demand and supply are equal. It is obvious that the number of units bought must be the same as the number sold. At the price 9, there can be and will be ten trades. In each of these ten trades there is some gain for each buyer and for each seller. (It matters not whether the most urgent buyer buys from the most urgent seller.) But not one of the buyers with a valuation less than 9 could trade with any of the sellers with a valuation more than 9. The only way in which any one of these excluded buyers or sellers could get into the trading would be by inducing some one on the other side to act by mistake contrary to his own interest, or from motives of pity or generosity, while at the same time one on the same side fails to act in accord with his own interest.4
It appears then that a logical market-price5 is that price common to all trades made at the time, which permits the maximum number of transfers with some gain to both parties. This may be expressed also as: that price common to all trades at a given moment, at which no less urgent bidder on either side of the market can trade while any more urgent bidder is excluded. Such a price brings the desires underlying demand and supply to an equilibrium; no buyer is willing to bid more and no seller is willing to take less. It may therefore be called an equilibrium price.
§ 4. The market as a two-sided auction. It may be helpful to think of the market as a double auction-sale in which each bidder in either group has in mind a “reserve-price,” a valuation at which he will withdraw from the market. Now suppose it is the duty of the auctioneer to find the correct market-price. He would say, “There are 16 axes here, how many will sell at 7 rather than not sell at all?” At this price there would be six sellers and only six trades possible. The other owners of axes hold them (have reserve-valuations) at more than price 7. “How many will buy?” At this price there are sixteen would-be buyers. Then by successive readjustments the auctioneer might finally fix a price at which the maximum number of trades is possible, that is, the price 9, with ten trades.
§ 5. Supply and demand coördinate in price-determination. It should be emphasized that in the foregoing explanation of price, choice must be understood in relation both to demand and to supply. Choice is not peculiarly connected with demand. Demand, like supply, means a quantity of goods which a person chooses to trade at the actual price. Demand is expressed as the number of sale-goods which a buyer will take at the price; supply as the number of sale-goods with which a seller6 will part. Demand and supply are the same goods viewed in different aspects. A trader can have no demand unless he has a supply of the price-goods to give, and will make no offer unless he has a desire for the other goods. There is no more of the psychological element in demand than in supply, and no less of the objective elements (of material goods).
§ 6. Price in a permanent market. We have been analyzing the process of price-fixing, starting at a moment when no price existed. Prices must have their origin in this way beginning in a given situation of human desires in relation to the existing fund of goods. But in a much greater number of cases in practical life to-day, price seems to exist in advance of, and apart from, any individual’s valuations. Almost every market, like every active business, is a “going concern,” closed only at night, on Sundays, and on holidays. Price seems to be a continuous fact, altho there is, properly speaking, no continuous price; there is merely a succession of separate prices, as shown by the trades from moment to moment. We watch price change as in a moving picture made up of many instantaneous photographs. Yet each new price seems to grow out of the last price. The opening price each day is usually somewhere near the closing price of the day before, but often somewhat, or very, different as a result of rumors, or of information regarding rains, wars, fires, and countless other influences. The individual trader must take the price at any moment as he finds it. His choice, indeed, is such a small element that price seems to be independent of his valuation. He merely decides whether at that price to buy, or to sell, the same amount as before, or more or less, or none at all, or to bid or to ask a lower or a higher sum. In doing any of these things, however, he not only indicates his attitude toward the market-price, but he exercises his influence upon it. An excluded buyer, if he has anything to trade, shows that he values the price more than he does the sale-good. On the other hand, an excluded seller, the owner of a sale-good, retains it because his desire for it is stronger than his desire for the price (and for the other things which by trade the price represents to him). Trade and the succession of prices appearing are the index and the resultant of the continuous changes in the economic conditions, desires, and choices of the members of the community.
§ 7. Effect of the market upon valuations. It is clear that price is the result of the valuations of traders in a market taken collectively; yet as each individual’s valuation is looked at separately it seems to be largely determined by price. It is very important to keep in mind that the valuations which are spoken of and represented graphically as so different from the market-price, are not actual. They are merely what would be if the individual were not in the market. It was shown in discussing the valuation curve (see Chapter 4, sections 8-11), of an isolated person, that the higher valuations of earlier units sink in accordance with the principle of diminishing gratification when more like units are added. The actual valuations of all the like units of a present supply are all alike (principle of indifference). Now in a market the individual is in the presence of large new supplies which he can buy at a price. If he approached the market with a higher valuation of the sale-good (in terms of the price-good) than he finds prevailing, he buys, and continues to buy successive units until his valuation of the sale-good has sunk to the market-price, or until his price-goods (purchasing power) are exhausted. So long as he keeps on buying he is bringing his valuation as nearly into agreement with the market-price as he can (with units of the size offered). As he gets more sale-goods their value (in money) falls (principle of diminishing gratification); as his money decreases the value of the other things he can buy with it relatively increases (principle of increasing gratification). When all his money is gone he has desire, but no demand, his valuation is merely hypothetical—what he thinks he would pay if he had the money. This is the state of mind of a large part of the population most of the time regarding most kinds of goods.
§ 8. The point of price-adjustment. Picture now a market, let us say a village, to which the farmers of the surrounding country are bringing eggs, butter, apples, etc. The price of eggs to-day is 20 cents a dozen, and at that price just 100 dozen are brought to market and sold. If but 80 dozen a day come to market the price will rise, let us say, to 25 cents. Altogether there must be 20 dozen fewer bought. Who ceases to demand eggs because price has risen only five cents a dozen? Some few wealthier families may continue to buy the same number as before, a few poorer families will stop using eggs entirely, and between these two extremes will be many families which will use eggs a little more sparingly. Now the group of poorest families, which before was buying some eggs, was just at the margin of choice as regards its whole demand; the middle group was just at the margin as regards a certain part of its demand. In the contrary case, say a fall of price from 20 to 18 cents, many of the families will somewhat increase their use of eggs (substituting them for other kinds of food and packing them for winter use), and perhaps still other families, which could before not afford to use eggs, will now buy some. And so with respect to every good, in a market of any size, there are always persons already buying some, who will be ready to buy more, and there are others not now buying any, who will begin to buy some, at a lower price. At the higher price they are excluded would-be buyers; in respect to certain quantities, they are merely potential buyers, but when the price falls they become actual buyers. (A similar view must be taken of the sellers, actual and potential, at a certain price.) Each price is clearly the resultant of all the actual demand and all the actual supply that brings about the equilibrium; but certain units both of demand and of supply are more responsive to price changes and are more immediately the occasion in bringing about changes than are others. The necessary adjustments of price, of demand, and of supply, are made by those traders who are in a most sensitive, unstable condition in reference to certain units of goods. Therefore our attention in studying price is directed more toward the buyers and the sellers who are just excluded, or are about to be excluded with any alteration of the conditions in the market. When the two pans of a balance are nearly in equilibrium, either a bit taken out of one pan or a bit added to the other will bring the balance to equilibrium. We speak of these bits added or taken away as causing the equilibrium, but we know that this is only on condition that the other contents of the pan are present and remain unchanged while this one change is made.
§ 9. Social factors in individual valuations. Men of to-day are accustomed to look to the market-price as in some measure a guide to their valuations. We have just seen why this must be so, because by trade men are constantly bringing their valuations into accord with that represented in price (so far as they have the purchasing power). But in still other ways, outside of trade and often preceding the actual trade, the influence of other men’s choices comes to play a large part in our valuations. Traditional and conventional values, foolish fashions, fads, and imitation of others in very different walks of life and with very different needs, modify and determine our choices. It is easy to see this in every one but one’s self. These phenomena are variously spoken of as the mob-mind, the hypnotism of the crowd, suggestion, snobbery, social ambition, idealism, etc. Each of us is so affected by his surroundings, his associates, his education from youth up, that even what seem to be our coldest calculations are based on these more or less fixed and fundamental standards of opinion, prejudice, and preference. Nevertheless, the individual’s choice, when he makes it, is his choice and helps to maintain or alter price. It will be recalled that from its very beginning choice was impulsive, not rational, and continues to be in a large part guided by habit as well as by impulse. Choice has become in part rational only as primitive impulses have been inhibited, and choice, which is action, has been postponed in view of larger interests.
§ 10. Objective conditions to be studied. In the foregoing analysis there is not an ultimate explanation of price;6 we must not think that price is fixed by choice rather than by the objective conditions affecting abundance of supply, etc. There is no such contrast between alternative explanations. Each choice is made in a given situation; so far as the choice is deliberate it is made in view of all the conditions, which include the abundance and scarcity of material things. It is impossible to conceive of choice determining price without having regard to the quantities and qualities of economic goods. In choice, men are at nearly all times touching the world of reality. In price, we see a most significant meeting point of economic forces. The market-price of the moment contains within itself many other problems the solution of which must be sought in a study of natural resources, inventions, machinery, growth of population, ability of men to produce, and many other concrete conditions of industry.
[1 ]This set of valuations with which a trader enters a market reflects a disposition, an attitude of choice, a provisional judgment, which is subject to change with new conditions. See below on social factors in individual valuations.
[2 ]Elasticity of demand. The changes of demand (and of supply) relative to a certain amount of change of price are very different according to kinds of goods, to times, and to circumstances. A fall of a particular price by 1 per cent may correspond with an increase of demand by 1 per cent or 2 per cent or 10 per cent as the case may be. When eggs were 35 cents a dozen in Chicago (between 1909-1911) and fell to 34 cents the change in demand was hardly noticeable. But at 30 cents (about 15 per cent less) the demand rose from about 15,000 cases to 30,000 a week (100 per cent),—a considerable degree of elasticity. (The standard case contains 30 dozen.). At 20 cents a dozen demand was remarkably elastic, and additional supplies to the amount of 50,000 to 100,000 cases were taken (probably used as substitutes for meat, and to put into cold-storage) with hardly noticeable decline in price. Later, in June and July, however, when the demand for cold-storage purposes falls off, and possibly because eggs are somewhat less palatable in hot weather, the price fell lower (to 18, and one year even to 15 cents). When at a given price a small reduction in price increases largely the amount that will be bought and sold, demand and supply are said to be elastic. For example, at 35 cents the demand for eggs in Chicago is relatively inelastic, and at 20 cents it is very elastic. See Fetter, Source Book in Economics, pp. 25-33, for description and diagrams of some seasonal price variations in food, from Professor H. C. Taylor’s study of the subject.
[3 ]It must not be thought that in the above diagrams B 1, B 2, B 3, etc., are necessarily all different people B 1, who is willing to pay (if he must) 14 for one unit, may appear again as B 2, willing to buy a second unit, but not willing to pay as much for it as he would for a single unit, or as B 4, B 6, etc. That is, he is willing, like the other buyers individually, and like the group of buyers as a whole, to take a certain sum at a high price, and a larger sum at a lower price. This is in accordance with the principle of diminishing gratification which we have already discussed (ch. 4). Similarly S 1 may enter again as S 2, S 5, S 6, etc. That is to say, each seller (of divisible amounts of goods) is willing to offer more at a high price than at a low price. It is evident, then, that the principle of diminishing gratification lies at the bottom of the demand conditions and also of the supply conditions as they exist in a market at any given time.
[4 ]Effect of trading outside of the market. For example, B 11 might take S 8 apart and persuade him to exchange at the price 8, at which both would gain something as compared with not trading at all. But it would be folly for S 8 to isolate himself in effect from the market in this way. For at that price there would be 8 traders willing to sell and 11 willing to buy. Three buyers able to outbid B 11 must, at the price 8, fail to get into the trade at all. One of them (logically it should be B 10 with a bid of 9) must leave the market without making a purchase (S 10 having a valuation of 9.5). Any buyer from B 11 to B 16 therefore could succeed in getting into the market only as a result of persuading one of the sellers against his own interest, and of outwitting a competing buyer. Similarly, S 11 might get B 9 apart (or any other buyer from B 1 to B 8) and make a trade at 9.5 mutually advantageous (tho not so good for B 9 as he might get otherwise). But at this price there would be 11 sellers and but 9 buyers, and as in the converse case, the less urgent traders would be displacing more urgent traders. Under the assumed valuations any other price than 9 involves the displacing of some more urgent bidder (or bidders) by a less urgent bidder on the same side.
[5 ]This is the logical, or theoretical, market-price in the sense that it is the price which results when all the assumed conditions are fulfilled. Actual market-price is that price at which a trade is made, and this may vary on either side of the theoretical price when something happens such as is described in the last footnote, some one failing to realize his possibilities. When this occurs there is immediately a new theoretical price and the increase of bids from the excluded, more urgent bidders must send the price either higher or lower than at the last trade. In the example above, where 8 was the actual price on one trade, the next theoretical price became 9½.
[6 ]Who is also, from the other point of view, a buyer, his sale-goods being the price he is ready to pay.
[6 ]It is easy “to confuse the idea of natural cause with that of final cause. Science knows nothing of the latter; any natural cause is only a link in the chain of cause and effect; it is itself the result of antecedent causes and the cause of subsequent results.” Conklin, “Heredity and Environment,” p. 164. This warning of the natural scientist is just as important in the social sciences as it is in biology.