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Nonfoods, and the Foods, Demographic Dacision to and Socioeconomic Characteristics Purchase Various Meats and sumption,” tribution on Seafoods for Home ConThe Journal of Food DisResearch, February 1980. ;: ;: A;t$c>kk*;k APPLICATIONS OF DEMANDRELATIONSIN THE FRESHFRUITAND VEGETABLEINDUSTRY by: J. E. Epperson, H. L. Tyan and C. L. Huang University of Georgia Athens, Georgia Problem Statement There is a definite need in the research community for estimates of demand relationships for specific fresh produce Such estimates are needed in i terns.order to study the impacts of different phenomena affecting the distribution of specific fresh fruits and vegetables. Examples of potential influences include: rising energy costs, urban encroachment of production areas, production restrictions due to dwindling water resources, and environmental restraints. A review of the literature reveals that there has not been a great deal accomplished concerning the estimation of demand relations for particular fresh produce items in the U.S. The most recent work, published in January 198o by Smith, pertains only to fresh winter and spring cucumbers and green peppers. George and King in 1971 estimated demand relations for an array of commodities. However, estimates were for the U+S. as a whole, and not market specific. In addition, periods of the year were not differentiated, and with few exceptions, Journal of Food Distribution Research demand relation estimates for fresh Droduce items were not mnsnodity specific. The works of Castro and Simmons, Bieri and deJanvry, and M ttelhammer include few fresh produce i ems and are not markets (consuming specific to regiona centers). Aside from the research purview, the business community may also have a desire for estimates of demand relationFor examships for planning purposes. ple, produce buyers or brokers may wish to know which produce items and markets have potential for expansion by time of The orientation of this paper year. concerns possible applications of demand estimates of particular fresh fruits and vegetables by the business community. Methodology and Data Sources Ordinary least squares was used to estimate demand functions for 16 fresh fruits and vegetables originating in the Southeast. The general form of the relationship for a given commodity, consuming center, year, and month is (1) P = f (Q, i,~)where P is price per hundred cwt February 81/page 135 (10,000 lbs.), Q is quantity in hundred cwt, I is income per capita, and & is a For statisvector of dummy variables. tical estimation dummy varibles were added to equation 1 to allow prices to vary by consuming center, month, and year; to allow the relationship between P and Q to vary by consuming center and month; and to allow the relationship between P and I to vary by market, The original data set encompasses ‘:i~ervations which are weekly for ]8 m.-kets from January 1972 through August ‘~5’?4 Price data (wholesale) were obr . tsined from the Agricultural Market $e~vice (AMS), USDA. Quantity data are urlpubl ished records of unload shipments September 1976) obtained [d~s~ontinued f~om the AMS. Income data were taken from the Survey of Current Business while population estimates are from the Departme:>t of Commerce. The data set is pooled crossThe pooled apsectional time-series. proach allows more degrees of freedom in st.,.~istical estimation which yields more efficient results than estimating separately by time period or market. Results —— Two functional forms were used to a linear form and a generate results: Results were quite similog-log form. lar using both forms. However, results reported here for selected commodities and consuming centers are from the loglog form since the price and income flexibil ities are represented directly from the coefficients. Results to follow which are depicted via tables involve only 7 commodities rather than all 16 partially bee. cause of space limitations and since only some of the fresh fruits and vegetables studied are needed to demonstrate the potential usefulness of estimated demand coefficients by commodity, market, This and time for decision making. February 81/page 136 demonstration cation section is attempted to follow. in the appli- Tables 1 through 7 depict the variability of price flexibil ities by month Each table is devoted to and market. a particular commodity: eggplant, watermelons, tomatoes, green peppers, cucumbers, sweet corn, and squash, reIn Table 1, a price flexispectively. bility of -0.493 in the Cleveland market in June means that a 10 percent increase (decrease) in shipments of eggplant to Cleveland results in a 4.93 percent decrease (increase) in the wholesale price. The meaning of price flexibility as illustrated may be interpreted in like manner throughout this paper. As can be seen from Tables 1 through 7, the data suggests that variability of price flexibility does indeed occur by market and month as well as commodity. Variability of price flexibility by market and month appears more acute for some fresh product items than others. For example, variability seems greatest for eggplant of the commodities presented, Tables 1 through 7. Price flexibil ities of 0.000 which appear in tables of this paper mean that the quantity coefficients were not significantly different from zero or that the quantity coefficients were positive. A positive relationship between price and quantity violates the general theory There could be several reaof demand. sons why the data would yield such unsatisfactory results. One plausible reason is perhaps that the time period was misspecified for some commodities and associated markets. A month might not be the relevant time period for observing market interactions. For example, a period of a week could be necessary to show the appropriate price-quantity relationship in some markets for certain fresh produce items. Another reason for zero or positive relationships between price and quantity might be that other variables such as unmeasured tastes and Journal of Food Distribution Research Table 1. Price Flexibilitiesfor Eggplantby SelectedMonths andMarkets. Market June July August Month September October Novembeq Chicago Cleveland Dallas New Orleade Philadelph!i,a 0,000 0.000 -0,068 -0.112 -0,052 -0.018 -0.513 -0.607 -0.547 -0.563 -0.493 -0.493 -0.116 -0.056 -0.022 -0.002 -0.002 -0.072 -0.422 -0,457 -0.517 -o.&73 -0.402 -0.402 -0.356 -0.390 -0.336 -0.406 -0.450 -0.336 +.l)~a Othera -0.142 -0.082 -0.048 -0.028 -0.099 ities: Atlanta, a Other representsseveralmarketswhichhave identicalDrice flexibiI Baltimore,Boston,Cincirinati, Columbia,Detroit,‘KansasCity,Los Angeles,Louisville, New York, Pittsburgh,and St. Louis. ., Modths and Markets. Table 2. PriceFlexibilitiesfor Watermelonsby Selected” ,. ..- ., June Market ‘ July . .. Septainber Month AuRust ,. ,- ,. . ., OctObe~ Chicago‘ > -0.174 “’ -0.174 -0.174 -0.174 -0.174 -0.2%2 -ai222 New Orl~ane -0.222 -0.222 -0:222 0.900 0..000 Group Ab 0.000 0.000 Q..(XXJ -0.035 ; -0.035 ~ -0.035 L Group B -0.035 ‘ -0.035 a Group A represents3 markets,Dallas,Minnaipolis,snd St. Loud,~hich hav&:. identicalpriceflexibilities. b Group B representsseveralmarketswhichhave identicalprice flexibilities: Atlanta,Baltimore,Bostcn, Cincinnati,Cleveland,Columbia,Detroit,Kansas City, Loe Angeles,Louisville,New York, Philadelphiaand Pittsburgh. .,., -. .- ,,. .. ,. ~ June . ...! JUIY .,, ., . .. . . .. . . TabIe 3. Pric&F~exjBilitiesfor.Tbmatoeaby selectedMonths and Markets. Harket . .. Month August . .“ ,September .$ Octibe~ , ; Z* 7 . ‘~-o.534 -0.534 -0:534 -0,534 -0.534 ,. ::-.0,616., ~, -0.616. “!.-0.616, ~ -() ’;-136 -0.136 ‘:::% “ ::!;: ‘“ -o.i36 : :“’” “:”‘i’ Other -0.0s3 -0.083 “ :-0’: , OU’3>” -o;083 ‘ -o.~~3 ..,,~.; : a Other represen?.’a’ se$er’al” marketstiichEai@ ia&fitical pries ~” ‘‘ ~ ““ $.* Atlanta,Baltimore,Boston,Chicago,Cincinnati,Cleveland,Columbia,DatrOit, Semee City, Minneapolis,New Orleans,New York, PhiladelphiaPittsburghand Dallas Loe Angeies Louia~i1le St. Journal of Imuis. Food Distribution Research February 81/page 137 Tabla4. Rice Flexibilitiee for Green Peppers by Selected Monthe and Markata. Month Market May June July Auguet Chicago Loa, Angeles -0.126 -0.126 -0.126 -0.126 September -0.153 octo~ -0.126. -0.478 -0.450 -0.450 -0.450 -0.450 -0.450 -(jo~ol Louievil Ie -0.201 -0.201 -0.227 -0.227 -0.201 Othera -0.146 -0.146 -0.146 -0.146 -0.172 -0.146 tiae: Atlanta, a Othar representssaveralmarketswhichhave identicalprice flexlbili Baltimre,Boston,Cincinnati,Cleveland,Columbia,Dallae,Detroit, KaoeasCity,Minneapoiia, NewOrleana,New York,Philadelphia, Pittsburgh, and St. Louis. for Cucumbers by Salectedllonthe aad Markets. Tab& S. PriceFlexibilitiea Nmrket May Cincinnati -0.496 n~polis June 0.000 Other -0.0?7 -0.470 O.oao Month JUIY Aunuet -0.556 0.000 sePcamber -0.556 -0.556 4.s40 O.om O.000 O.aoo Octobqg -0.0s1 -0.137 -0.137 -o.la -0.137 ● eeveralxerketsvhichhava idaat Ch● r repreeeote icalpricef Iaxibilities: Atlanta, Ealtimere.Boston. Chicaao.Cle?dend.Columbia. Dallaa,Detroie,KaneaaCity, Leuiavillo. W Orlea&, New York,Pii%iadalphia, Pittsburgh* ●nd St.Louis. for Smet Corn by SelectedMaotha end ?I@kata. Table6. Prica Fla%ibilitiaa’ Market May O.000 -0.239 Chicago Lea Angel& NSoaeapeSi* St. 0.000 U4iti. Jima O*WO -0.23s a.oao nentll JOY -0.63s -0.28s o .Ooa. see- Atmmt -0.037 4$87 0.600 -0..0s0 -0.329 a.000 ‘ ,, February 81/page 138 Table Price 7. Flexibil ities for Squash by Selected Months and Markets. Mont h Market April May June July August September October November Baltimore -0,355 -0.355 -0.302 -0.381 -0.248 -0,355 -0.329 -0.355 I@uisvi 1le -0.263 -0.263 -0.289 -0.210 -0.157 -0.263 -0.238 -0.263 Phila~elphis -0.485 -0.485 -0.512 -0.433 -0.379 -0.485 -0.485 -0.460 -oql~8 Other -0.1s1 -0.181 -0.207 -0.075 -0.156 -0.181 -0.181 a Other representsseveralmarketswhich have identicalprice flesibilities:Atlanta.Boston. Chicago,Cincinnati,Cleveland,Columbia,Dallas,Detroit;Loa Angeles,Minneapolis, -N;w ‘ Orlesns, New York, Pittsburgh,and St. LOuie. ng factors given preferences for overrid quantity, the ranges in values of price, the data and per capita income w thin In addition to set used in this study. the reasons given, there is always in any study the issue of validity of the data used in this data. The unload study does not account for total quantity consumed in a given market and time However, every effort is made by period. Price dependent rather the AMS to do so. than quantity dependent demand functions were used in this study to negate the possible hazards of incomplete quantity For the kind of spatial information. and temporal research embodied in this study there is no other source of data than reported unloads by the AMS. cent rise (fall) in the wholesale price of watermelons in most markets, Table 8. Other income flexibil ities may be interpreted in a similar manner, An attempt will be made to show the value of income flexibility information in the application section of this paper, Conclusions Results are supportive of expected differences in demand relations by commodity, consuming center, and month. Results also support the work of Smith regarding price flexibilitiesl which were shown to be inflexible (absolute value less than 1) for spring and winter fresh Since cucumbers and green peppers. price flexibil ities for all commodities in all markets in all months were inflexible, the implication is that there is a great deal of substitution among produce items and perhaps with other related Research is now underway to commodities. determine the extent of substitution among fresh fruits and vegetables by consuming center and month. Price flexibil ities of 0.000 as shown for June and July in the Chicago market for eggplant, Table 1, do not mean that the Chicago market can be fiooded with eggplant during June and July without serious detriment to price. Rather, it indicates that based on the data, the Chicago market has been unchallenged in this respect. Of course, the same logic applies regardless of fresh produce item, market, or month. Application Food Industry To illustrate the existence of variability of income flexibility by commodity and market, Table 8 is presented. An income flexibility of 1.729 for watermelons means that a 1 percent rise (fall) in per capita income yields a 1.729 per- Planning for potential change is Firms reimportant in any industry. sponsible for procuring or channeling fresh produce can use flexibility estimates from demand relations to ascertain the impact of changing supplies, consumer Journal of Food Distribution Research to the February 81/page 139 Table 8. Income Flexibili.ties for Selected Fresh Vegetables and Fruits by Market. Commodity Flarke t Eggplant Watermelons Atlanta ().592 1.729 Baltimore 0.023 lloston Chicago C.i.ncinnati Cleveland 0.592 0.592 0.592 0.716 (lolumbia C%llas 0.592 0.592 I)etroit Kansas City Los Angeles Louisville Minneapolis New Orleans 0.592 0.592 0.592 0.592 ().592 0.743 1.709 1.729 1.729 1.729 1.729 1.709 1.729 1.729 1.729 1.729 1.729 1.729 1.729 York Philadelphia 0.592 0.592 Pittsburgh St. Louis 0.592 0.592 1.729 1.729 New Tomatoes 0.419 0.407 Green Peppers squash 0.419 0.419 1.999 0.419 0.419 0.721 0.419 0.419 0.419 0.419 ().419 0.419 1.091 1.091 1.091 1.091 1.358 1.091 1.091 1.091 1.091 1.091 -0.362 1.091 1.091 1.091 1.729 0.419 0.615 1.091 0.000 1.729 1.359 0.605 1.091 0.000 0.419 0.419 0.605 0.605 1.091 0.000 1.091 0.000 It should be pointed out that this application exercise is based on a micro That as opposed to a macro perspective. is, the exercise pertains to possible actions of an individual firm rather than For example, if the an entire industry. entire industry flooded the Dallas market with watermelons in June, Table 9, this would constitute a change far beyond the limits of the data used in this study to estimate demand relations and would obviously have a substantial impact on price. income flexibil ities for all in Table 9 are greater than 1 means that changes in prices in markets for associated comrnod! ties 0.000 0.000 0.000 0.000 0.023 0.000 0.000 0.009 0.022 0.000 0.205 0.013 0.000 0.000 ~ 1.307 1.343 1.307 1.307 1.307 1.307 1.307 1.307 1.307 1.307 0.428 1.307 1.307 1.307 1.318 1.410 0.743 1.307 tend to be quite responsive to changes in per capita income based on the data used in this study. From Table 9, watermelons, cucumbers, and squash appear to show the greatest proportionate potential for most markets in June. Also, the implication is that increased shipments of these commodities should be considered for markets anticipating Table 10 is similar to income growth. Table 9 except that income flexibiliThus ties for entries are less than 1. the long term possibilities are not as great for commodities and associated However, markets depicted in Table 10. the ranking short-run wholesale procedure as it pertains price. applies to in the effects on REFERENCES Bieri, entries wh~ch these Sweet Corn 0.605 0.605 0.605 0.605 0.605 0.605 0.605 0.618 0.605 0.591 0.605 0.605 0.619 0.605 i ncome, and population on the price of For example, specific product items. Table 9 ranks markets and associated commodities proportionately for June in an effort to identify markets that can absorb greater supplies without serious detriment to wholesale price. The Cucumhers J. and Analysis Budgeting, Monograph Californiaj A. of deJanvry, Empirical Demand Under Consumer Giannini Foundation No. 30, University of September l~?:, , , Table 9. Ranking of Markets and Associated Commodities for June According Price Flexibility with Income Flexibility Greater than 1. Ranka Market to Price Flexibility Commodity Dallas 0.000 Watermelons Minneapolis Watermelons 0.000 0.000 St. Louis Watermelons : Minneap lis Cucumbers 0.000 E 5 Group A -0.035 Watermelons 6 Group Bc Cucumbers -0.051 -0.083 7 Tomatoes Cincinnati Philadelphia 8 Tomatoes -0.083 Watermelons Chicagod -0.174 9 -0.207 Squash Group C 10 11 New Orleans Watermelons -0.222 Louisville 12 -0.289 Squash 13 Baltimore Squash -0.381 Philadelphia 14 Squash -0.512 15 Cincinnati Cucumbers -0.560 greatest proportionate potential for expansion. al= b Group A represents: Atlanta, Baltimore, Boston, Cincinnati, Cleveland, Columbia, Detroit, Kansas City, Los Angeles, Louisville, New York., Philadelphia, and Pittsburgh. c Atlanta, Baltimore, Boston, Chicago, Cleveland, Columbia, Dall,as, Detroit, Kansas City, Los Angeles, Louisville, New Orleans, New York, Philadelphia, Pittsburgh, and St. Louis. d Atlanta, Boston, Chicago, Cincinnati, Cleveland, Columbia, Da],las, Detroit, Los Angeles, Minneapolis, New Orleans, New York, Pittsburgh, and St. Louis. 1 2 Castro, The Demand R. and R. L. Simmons, Cucumbers, and for Green Pep pers, Cantaloupes in the Winter Season, Econ. Res. Rept. No. 27, North Carolina State University, Raleigh, April 1974. Federal-State ~ Prices, 1972-1976. George, USDA, News AMS, Service, selected cities, of R. C., Demand Food The for Distribution A Priori Information, Washington State Ph.D. University, Smith, The Demand for Fresh Winter E. B., Cucumbers and Green Peppers in U.S. Regional Wholesale Markets, USDA, ESCS, January 198o. Us. Department Estimates P-25, No. Us. Department Current Fresh P. S. and G. A. King, Consumer Demand for Food Commodities in the United States with Projections for 1980, Giannini Foundation Monograph =26, March 1971. Mittelhammer, Domestic Journal Market Using thesis, 1978. of and 704, Commerce, Population Projections, Series July 1977. of Commerce, Business, various Survey of issues. Estimation of Salad Vegetables Research February 81/page 141 Table 10. Ranking of Markets and Associated Commodities for June According to Price Flexibility with Income Flexibility Less than 1. Ranka Market ~ Price Flexibility, Commodity Eggplant 0.000 0.000 Sweet Corn Sweet Corn 0.000 0.000 Minneapolis 4 Sweet Corn Dallas 5 Eggplant -0.002 6 Group B= Eggplant -0.028 7 -0.051 Los Ang$les Cucumbers -0.083 8 Tomatoes Group C 9 New York -0.095 Sweet Corn -0.126 10 Chicago Green Peppers 11 Louisvi&.le Tomatoes -0.136 12 Group D Green Peppers -0.145 -0.201 :[3 Green Peppers Louisville 14 Pittsburgh Squash -0.207 -0.207 Squash 15 Los Angeles 16 Los Angeles -0.239 Sweet Corn -0.336 17 Philadelphia Eggplant 18 New Orleans Eggplant -0.402 19 -0.450 Los Angeles Green Peppers 20 Cleveland Eggplant -0.493 Dallas -0.534 21 Tomatoes 22 Los Angeles Tomatoes -0.616 a 1 = greatest proportionate potential for larger quantities of unloads. b Group A represents: Atlanta, Baltimore, Boston, Cincinnati, Cleveland, Columbia, Dallas, Detroit, Kansas City, Louisville, New Orleans, Philadelphia, Pittsburgh, and St. Louis. c Atlanta, Baltimore, Boston, Cincinnati, Columbia, Detroit, Kansas City, Los Angeles, Louisville, New York, Pittsburgh, and St. Louis. d Atlanta, Baltimore, Boston, Chicago, Cincinnati, Cleveland, Columbia, Detroit, Kansas City, Minneapolis, New Orleans, New York, Philadelphia, Pittsburgh, and St. T.ouis. e Atlanta, Baltimore, Boston, Cincinnati, Cleveland, Columbia, Dallas, Detroit, Kansas City, Minneapolis, New Orleans, New York, Philadelphia, Pittsburgh, and St. Louis. Chicagg GroupA Chicago 2 3 February 81/page 142 .@urnal of Food Distribution Research