INCOME, EDUCATION AND AGE EFFECTS ON MEAT AND FISH DEMAND IN TUNISIA

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1 Iteratoal Joural of FoodadAgrculturalEcoomcs ISSN Vol. 1 No. 2 pp INCOME, EDUCATION AND AGE EFFECTS ON MEAT AND FISH DEMAND IN TUNISIA Mohamed Zed Dhraef Laboratory of Agrcultural Ecoomcs, Natoal Isttute of Agrcultural Research of Tusa. Street Hed Karray, Araa 2049, Tusa Tel/Fax : , E-mal mz_dhraef@yahoo.fr Merem Oueslat Laboratory of Agrcultural Ecoomcs, Natoal Isttute of Agrcultural Research of Tusa, Tusa Boubaker Dhehb Socal, Ecoomc ad Polcy Research Program, Iteratoal Ceter for Agrcultural Research the Dry Areas (ICARDA), Amma-Jorda Abstract Soco-ecoomc ad demographc varables ca have a deep mpact of the demad for food. The obectve of ths work s to aalyze how these varables ca affect the demad for meat ad fsh for Tusa cosumers. Ths study covers two mportat aspects: the omposto of, a pror, a fuctoal form ad the use of cross-secto data cludg demographc ad socoecoomc varables. Relatos amog meat ad fsh through cross prce elastctes ca be substtutos or complemetary. The cosumpto of these products patters by age, level of come ad level of educato. Ths cosumpto s relatvely dfferet as regards to the ecoomc factors (food expedture ad prce). Elastctes expedture for beef ad mutto creases wth age whereas elastctes expedture for chcke ad fsh decrease wth age. Age s a maor factor cosumg meat ad fsh as t tegrates health dmeso. These results mply that chages ecoomc ad demographc factors ad creasg health awareess have flueced the chages meat ad fsh demad Tusa. Key words: Food demad aalyss, socoecoomc ad demographc varables, Tusa 1. Itroducto Tusa as a Medterraea coutry has for a log tme food culary tradtos smlar to the Medterraea det. The Tusa det s characterzed 2010 by a cosumpto of cereals (181 kg/perso/year), fruts ad vegetables (145 kg/perso/year) ad mlk (95 kg/perso/year). The cosumpto of meat, poultry ad fsh s about 39 kg/perso/year accoutg for oly 5.3% of the total food products cosumed 2010 (INS, 2010). The cosumpto of meat ad fsh has udergoe a sgfcat evoluto over the past two 1

2 Icome, Educato, ad Age Effects o Meat ad Fsh decades. Betwee 1990 ad 2010, cosumpto of poultry ad fsh grew remarkably respectvely by 138% ad 36%. Sheep meat cosumpto creased by 24% whle beef decreased by 32% over the same perod. The expedtures have cocurretly creased for mutto (102%), poultry (143%) ad fsh (206%). The remarkable crease fsh expedture reflects the ew cosumpto patters amog the Tusa cosumer. Beef expedtures creased by almost 50% despte the drop ts cosumpto due to the crease the prce (INS, 2010). These chages reflect the chage food habts of the Tusa cosumer. Sce the 1990 s, food demad has had sgfcat chages related partcularly to urbazato process, ew lfestyles, dustralzato of food sectors, woma work, the emergece of moder retal ad creasg utrtoal health cocers. Food habts are chagg rapdly wth the ew soco demographc characterstcs of the Tusa populato. Ideed, age, level of come ad educato level are thus mportat factors purchasg decsos a coutry where 55% of the populato has a age lower tha 30 years 2010 ad whose educato ad come s mprovg day by day (INS, 2010). The lterature o demad aalyss of meat ad fsh s very dverse (Brester & Wohlgeat, 1993; Graca & Albsu, 1998; Wlso & Marsh, 2005;Jabar, 2005;Talaard, Va Schalkwyk& Alemu, 2006).From a methodologcal pot of vew, most of the metoed researches are lmted two ways: O the oe had, they mpose a pror a partcular fuctoal form for demad equatos (Almost Ideal Demad System, Rotterdam, Cetral Bureau of Statstcs, GADS) wthout testg whether a alteratve model mght better ft the data; o the other had, these works oly cosder oe dmeso of the data (tme seres). Cosderg a cross secto dmeso would substatally mprove the precso of the estmates of the parameters of the models, although we must recogze the dffculty of coductg such studes Tusa due to the lack of formato to buld a real cross secto at a atoal level. I Tusa, the aalyss of the meat ad fsh cosumpto was the subect of several studes usg atoal ad teratoal tme seres statstcs data bases (Be Kaaba, Dhehb& Gl, 2000; Dhehb& Gl, 1999; Dhehb, Gl &Agulo 2001; Dhehb& Gl 2003). However, to the author s kowledge, o study has assessed the patters of meat ad fsh cosumpto Tusa usg cross secto data ad estmatg the mpacts both of ecoomc (prce, come) ad soco-demographc factors (age, educato). The am of ths works to aalyze the mpact of soco-ecoomc ad demographc varables o the demad for beef, mutto, chcke, turkey ad fsh amog Tusa cosumers usg cross secto data ad dfferet fuctoal forms of food cosumer s models. The outle of ths paper s as follows: Secto 2 develops the emprcal model ad the estmato procedure. Results ad dscusso are preseted Secto 3. Fally, secto 4 outles the cocluso ad polcy mplcatos draw from ths study. 2. Methodologcal Framework 2.1. Theoretcal model Classcal demad theory cosders the behavour of a dvdual cosumer who wshes to maxmse ts utlty fucto, subect to a budget costrat: Max. u(q) u(q 1,q 2,..., q ) S.a p m 1 q =1,..., (1) Where u s utlty; q, p, are quatty ad prce for food respectvely; ad m s the total expedture or come. 2

3 M. Z. Dhraef, M. Oueslat, B. Dhehb The demad equatos satsfyg (1) have the geeral form: q f (m,p 1...p ) (2) The equato of demad obeys to several restrctos expressed terms of elastctes whch are dervatves of the logarthmc verso of (2). The logarthmc dfferetal of (2) s dlq η dlm μ dlp (3) Where s the come elastcty of demad for good, s the ucompesated, owprce elastcty, ad the ( ) are the cross-prce elastctes. Demad equatos (2) were approxmated by double-logarthmc specfcatos wth costat elastctes. Eve f ths approxmato could ft the data ad geerate plausble estmates of the elastctes, t s ot well suted to vestgate the restrctos of classcal demad aalyss. The addg-up restrcto caot be geerally satsfed by the double-logarthmc specfcato (Deato, 1989; Barte, 1993) Rotterdam System (ROT) Thel (1965)developed the Rotterdam model by replacg by e the logarthmc dfferetal equato (3), usg the compesated prce elastctes: dlq η (dlm w dlp ) e dlp (4) The he multpled both sdes through by w to obta: w dlq b (dlm w dlp ) s dlp (5) The margal shares b = w ad the Slutsky coeffcets s = w e are cosdered as costats. The frst term brackets (5) ca be read as the chage oe partcular logarthmc measure of real come dlq = dl(m/p) where dlp w dlp s the Dvsa prce dex. Cosderg the logarthmc dfferetal of the th budget share s a aother way for calculatg the real come term: dlw dlp dlq wlm (6) The we multply both sdes through by w : w dlw dw w dlp w dlq dlm (7) Sum (7) over all : dw 0 w dlp w dlq dlm (8) Therefore, dlm 1 w dlp wdlq dlq (9) 1 3

4 Icome, Educato, ad Age Effects o Meat ad Fsh Ad the real come term dlq w dlq s recogsed as the Dvsa quatty dex 1 for the chage real come. Cosderg ths defto, the Rotterdam model ca be rewrtte as: w dlq b dlq s dlp (10) Almost Ideal Demad System (AIDS) The ext model cosdered ths work s the Almost Ideal Demad (AID) system developed by Deato ad Muellbauer (1980) wrtte as follows: * w d c (lm lp ) r lp (11) Where, 1 lp * α 0 d k lp k r k lp k lp 2 (12) k 1 k 1 Stoe s dex gves a approxmato for (12): * lp w lp (13) k The wth (13) substtuted to (11), we have the AIDS system levels: w d c (lm w lp ) r lp (14) The dfferetal verso of (14) ca be wrtte as follows; we add a costat to each equato to represet autoomous treds demad: dw γ c dlq r dlp (15) The AIDS s very smlar to the Rotterdam model equato (10), eve f the depedet varables are dfferet. Ths model explas the chage the budget share of each good, whlst the Rotterdam model cosders oly the quatty compoet, w dlq, of the budget share chage. The AIDS model (15) ad the Rotterdam model (10) are smlar some ways. Thus, ther coeffcets are lked the followg way: If we replace w dlq (7) by the rghthad sde of the Rotterdam model (10), ad replace dlmby dlq w dlp, we obta: Where =1 f =, 0 otherwse. Equato (16) s detcal form to the AIDS model (15), whch reveals that the AIDS ad Rotterdam coeffcets are lked through the followg way: c b w (17) (16) 4

5 M. Z. Dhraef, M. Oueslat, B. Dhehb r s w δ w w (18) Cetral Bureau of StatstcsCBS System Keller ad Va Drel developed the CBS system (Keller & Va Drel, 1985).Ths model has the AIDS come coeffcets c ad the Rotterdam prce coeffcets s. It s formed by replacg b (10) by c +w ad subtractg w dlq from both sdes. The CBS system ca be wrtte as: w (dlq dlq) γ c dlq s dlp (19) I ths case, the depedet varable s the (w -weghted) devato of the log chage q from the (w -weghted) average log chage the quattes of all goods. The left-had sde s the weghted chage the volume share, q /Q, of the th product NBR System Nevesdeveloped the NBR model whch has the Rotterdam come coeffcets ad the AIDS prce coeffcets (Neves,1994). If we replace c the AIDS system (15) by b -w ad move w dlq over to the left-had sde, we obta the NBR system: dw w dlq γ b dlq r dlp (20) 2.2. Data, ad estmato procedure Data Data was collected o sprg 2008 amog a sample of 504 heads of households dstrbuted equally amog seve regos of Tusa. Accordg to the geder, the sample was predomatly composed of me (90.67%). Moreover, about 92.46% of those tervewed were marred. The sample was dvded to fve age groups. The educato level had two domat levels: hgh school ad the upper level represetg 41.67% ad 34.13%, respectvely. The varable come was dstrbuted amog sx come classes. The class of less tha 143 US $ s cosdered as the poorest class correspodg to households wage below the mmum requred. Ths class represets oly 3.17 % of the sample (See Table 1) Estmato procedure The Rotterdam, CBS, AIDS, ad NBR models are defed a dfferetal form. To obta estmable equatos they have to be coverted to fte chages. We follow the usual practce of approxmatg w t, dlp t ad dlq t for, ad, respectvely, where subscrpt t dcates tme. The four emprcal models have bee estmated usg the Full Iformato Maxmum Lkelhood (FIML) procedure the TSP4.4 program. The "fsh" equato was deleted to avod sgularty of the varace ad covarace matrx of resduals due to the addg-up restrcto. Restrctos mposed by ecoomc theory (homogeety ad symmetry) were mposed each model order to obta results cosstet wth the ecoomc theory. 5

6 Icome, Educato, ad Age Effects o Meat ad Fsh Table 1. Soco-demographc statstcs of the sample, N=504 (%) < Age (years) >60 Illterate Corac school Educato Level Prmary school Secodary school Hgher school < 143 US $ US $ US $ Icome (per moth) US $ US $ > 1072 US $ Source: Feld survey, Emprcal model The four competg demad systems (10, 16, 19 ad 20) are ot ested. To asses ad compare the emprcal performace of each of the four codtoal systems, we employed Barte s (1993) o-ested testg procedure. However, the sythetc model ests all demad systems: (21) Where; ; ; ad 1 ad 2 are addtoal parameters: 1) whe 1 = 2 =0, system (21) reduces to the Rotterdam. Whe 1 =1 ad 2=0, system (21) reduces to the CBS. Whe 1 = 2 =1, system (21) reduces to the AIDS ad whe 1 =0 ad 2 =1, system (21) reduces to the NBR. These parametrc restrctos satsfy the theoretcal restrctos of addg-up, homogeety ad symmetry, mpled by demad theory : k Addg-up : d 0, e 0 (22) 1 k Homogeety : e 0 (23) Symmetry : e e (24) Sce the four systems satsfy the addg-up, homogeety ad symmetry, the secod step cossts o a comparso betwee the four competg systems. For comparso, a lkelhood rato test ad Barte s (1993) test are used(dhehb, Gl & Agulo, 2001). The Lkelhood Rato Test (LRT) for model selecto s: k 1 LRT = -2 l L( * ) l L( ) (25) 6

7 M. Z. Dhraef, M. Oueslat, B. Dhehb Where s the vector of parameter estmates of a restrcted model (Rotterdam, CBS, AIDS, ad NBR) ; * s the vector of parameter estmates of the sythetc model; ad L(.) s the log value of the lkelhood fucto (Thel, 1965). Table 2 presets the log values of the lkelhood fucto ad the correspodg statstcs for model selecto. I par-wse lkelhood rato tests betwee the sythetc model ad the four dvdual systems, the Rotterdam, dfferetal AIDS, ad NBR were frmly reected by the hybrd model. The CBS system was the oly system to be ot reected (at least at the 5 percet level). Table 2. Tests results for the competg demad models ad the sythetc system: lkelhood rato test statstcs ad Goodess of ft Demad Systems Maxmsed Log Lkelhood Lkelhood Rato Test: amed demad system v. Goodess of Ft R 2 the sythetc system. a Sythetc System b ROT CBS AIDS NBR a. Wth two degrees of freedom, the crtcal value at the 5% sgfcace level s The 1% crtcal value s b. The estmates for 1 ad 2 (23) are 1.06 ad 0.16 wth stadard errors ad 0.136, respectvely. Source: Feld survey, To coclude, we have see that CBS model s the best specfcato that ft wth data aggregated over cosumers. Thus, the emprcal model has the followg expresso: w (dlq dlq) γ c dlq s dlp (26) Where parameters are explaed the prevous sectos. Moreover, applyg lear restrctos o the estmated parameters homogeety ad symmetry restrctos are satsfyg. The expedture elastcty of each commodty group ( ), the ucompesated prce elastctes (E ) ad the compesated prce elastctes ( ) for the CBS model are: - Total expedture: η c 1 (27) w s - Ucompesated prce elastctes: E η w (28) w - Compesated prce elastctes: 3. Results s ε (29) w Table 3 shows ow prce ad expedture elastctes for beef, mutto, poultry ad fsh. The expedture has a postve ad sgfcat mpact o the cosumpto of meat ad fsh. Beef ad mutto are luxury goods whle poultry ad fsh are ecessty goods. All ow prce elastctes are egatve. Nevertheless, the fsh has a elastcty prce whch s superor to oe whch dcates that the demad for fsh s relatvely elastc. The perod of the cosumpto of fsh seems to expla ths expedture elastcty compared to the other products. Beef ad mutto demad s less elastc as show by the less tha oe ow-prce elastctes spte of 7

8 Icome, Educato, ad Age Effects o Meat ad Fsh the hgh prces of these products compared to the others (See table3). Poultry demad s elastc to ay chages ts prce. Table 3.Expedture ad ow prce elastctes Products Elastctes Expedtures Prces Beef 1.06** -0.66** Mutto 1.35** -0.88** Chcke 0.73** -0.39** Turkey 0.43** -0.26** Fsh 0.61** -1.19** ** sgfcace at 5% level. * sgfcace at 10% level. Source: Feld survey, We observed substtutos or complemetary relatos amog meat ad fsh after aalyzg the cross prce elastctes. The dagoal of the hcksa matrx show Table 4 s composed by sgfcat ad egatve prce elastctes. Mutto substtutes ay type of meat. Beef substtutes mutto, chcke ad fsh. Chcke substtutes beef ad mutto. Fsh substtutes also mutto ad chcke. Turkey does ot substtute ay type of meat because t was recetly troduced to the culary practces of the Tusa cosumer. Table 4: Cross prce elastctes Products Beef Mutto Chcke Turkey Fsh Beef -0.42** 0.22** 0.17* Mutto 0.14** -0.40** 0.09* ** Chcke 0.16** 0.14* -0.22** ** Turkey ** * 0.25 Fsh 0.61** 0.60** ** ** sgfcace at 5% level. * sgfcace at 10% level. Source: Feld survey, Beef ad Mutto are et substtutes because they are cosdered as essetal the tradtoal ktche. Tables 5, 6 ad 7 show the results of meat ad fsh demad: the expedture ad rce elastctes are dfferetated by educato level, age ad household come. Expedture elastctes by educato level are superor to oe whch s cosdered as a luxury product for beef ad mutto except for beef for cosumers wth a hgh level of educato. Poultry ad fsh are ecessary products except turkey bought by llterate cosumers or those havg corac or prmary educato. The hgh prce of turkey compared to chcke ad fsh could expla the classfcato of ths type of meat as a luxury product for ths type of cosumer (See Table 5). Geerally, cosumers wth a hgh level of educato are more cocered by health tha those wth a low level of educato. Ths result explas the hgh quatty of fsh ad meat purchased wth a low level of greases. The less expedture elastctes of chcke, turkey ad especally fsh for cosumers wth hgh level of educato cofrm ths realty. 8

9 M. Z. Dhraef, M. Oueslat, B. Dhehb Table 5. Ow prce ad expedture elastctes by educato level of the head of household Illeterate, corac Secodary studes Hgher studes Products ad prmary studes Expedtures Prces Expedtures Prces Expedtures Prces Beef 1.09** -0.84** 1.01** ** -0.85** Mutto 1.33** -0.85** 1.38** -0.91** 1.38** -0.97** Chcke 0.76** -0.18* 0.78** -0.55** 0.68** -0.44** Turkey 1.10** * Fsh 0.65** -0.12* 0.61** -0.17** 0.52** -0.11** ** sgfcace at 5% level. * sgfcace at 10% level. Source: Feld survey, Emprcal results for ow prce elastctes of meat ad fsh by level of educato show are egatve agreemet wth the ecoomc theory ad lower tha oe. Most of the coeffcets reported the table are tutvely reasoable. The demad for chcke meat s less elastc tha the demad for beef ad mutto. Nevertheless, t s more elastc tha the demad for fsh. I ths case, the ow prce elastctes for fsh s low compared to the other products. Ths shows that the Tusa cosumers are sestve to ay chages the prce of fsh. Cosequetly, a crease the expedture of fsh s ot the result of lower prces, but of a rse the come ad probably also because of the terest for the health by cosumers. Expedture elastctes by age (See table 6) show that beef ad mutto are luxury goods except beef for youg cosumers (age lower tha 40 years). Chcke ad fsh are ecessary goods for all types of cosumers. Elastctes expedture for beef ad mutto creases wth age whereas elastctes expedture for chcke ad fsh decrease wth age. Age s a maor factor cosumg meat ad fsh as t tegrates health dmeso. Ths s cofrmed by a hgh elastcty for mutto meat (1.5) ad a low elastcty for fsh (0.45) for the Tusa cosumers aged more tha 50 years. I fact, oldest cosumers decrease ther cosumpto of mutto meat whch s rch amal greases ad crease ther cosumpto of fsh whose beefts are recogzed (See Table 6). Table 6: Ow Prce ad expedture elastctes by age of household head Products AGE1 < 40 years AGE2 from 40 to 50 years AGE3 > 50 years Expedtures Prces Expedtures Prces Expedtures Prces Beef 0.96** ** -1.27** 1.11** -0.53* Mutto 1.29** -0.64** 1.35** -1.12** 1.45** -0.80** Chcke 0.86** -0.58** 0.73** -0.57** 0.65** Turkey 0.51** Fsh 0.69** -0.19** 0.60** -0.34** 0.45** -0.05** ** sgfcace at 5% level. * sgfcace at 10% level. Source: Feld survey, The ow prce elastctes by age are the maorty of cases sgfcat. The demad for beef ad mutto s elastc to ay chage ther prces for the category of age betwee 40 ad 50 years. For the others, ths demad s relatvely elastc. Ths varablty demad elastcty cofrms the effect of age beef ad mutto cosumpto. The demad for fsh s 9

10 Icome, Educato, ad Age Effects o Meat ad Fsh elastc for the age category more tha 50 years. Ths cofrms that fsh cosumpto s ot depedet o ts prce but o health aspects. Table 7 shows ow prce ad expedture elastctes by level of come. Emprcal results pots outthat beef ad mutto are luxury goods except beef for cosumers wth a mothly come betwee 286 ad 714 US $. Poultry ad fsh are ecessary goods for all categores of come. Table 7: Ow Prce ad expedture elastctes by come Icome RVN1 RVN2 RVN3 Products Expedtures Prces Expedtures Prces Expedtures Prces Beef 1.23** -0.76** 0.91** ** -1.31** Mutto 1.21** -0.61** 1.48** -1.17** 1.31** -0.85** Chcke 0.81** -0.29* 0.78** -0.40** 0.52** -0.52** Turkey 0.67* 1.48* ** Fsh 0.71** -0.13** 0.45** ** 0.09** ** sgfcace at 5% level. * sgfcace at 10% level. RVN1: Mothly come <286 US $, RVN2: Mothly come betwee 286 ad 714 US $, RVN3: Mothly come > 714 US $. Source: Feld survey, The ow prce elastctes by level of come are ot all egatve ad are postve for two cases. The frst case relates to turkey meat belogg to the category of cosumers wth a come lower tha 286 US $. The secod case cocers fsh bought by the cosumers havg a come hgher tha 714 US $. Ths seems to be explaed for turkey meat by the volume of purchase whch s deftely lower tha the volume of purchase of the other products. Ideed, the maorty of the purchases of turkey meat do ot exceed the half-klo. Cocerg fsh whch s ofte cosumed summer, eve f ts prce creases, the cosumed quatty creases because the perodcty of ths product. Comparg to the other kd of meat (Beef, mutto, poultry), mackerels ad sardes have a lower prce. Eve f there s a augmetato the prce t has o effects o ts cosumpto. The demad for beef ad mutto for the cosumers wth a come hgher tha 714 $ ad the demad for mutto meat for the cosumers wth a come betwee 286 ad 714 $ are elastc to ay chages of the prce. Demad elastcty for chcke meat creases wth the come. I spte what t seems to be ormally observed, the cosumers wth a hgh come are the most sestve to the chages the prce of chcke. I other words, they beeft from a reducto prces of ths product to crease the quatty bought. 4. Cocluso ad Polcy Implcatos I ths paper we examed the cosumers habts of food Tusa, from the stadpot of the quattes cosumed of meat ad fsh, to chages tradtoal ecoomc varables, come ad prces, ad certa demographc ad socoecoomc varables. Ths research has focused o the estmato of demad systems usg cross-secto data, thus a sythetc system was selected gvg certa restrctos o ts parameters. The selecto of a fuctoal form a pror would have meat the loss of sgfcat formato. The results terms of elastctes are comparable to other studes (Dhehb & Gl, 1999, 2003) prmarly those who have used tme seres data although there are some dffereces the expedture ad prce elastctes magtude. The aggregato of meat ad fsh ad the characterstcs of the source of formato used were udoubtedly the ma drvers of ths work by makg t dffcult to compare results. 10

11 M. Z. Dhraef, M. Oueslat, B. Dhehb I ay case, we beleve that the strategy used our research s adequate ad provdes greater flexblty ad cosstecy the estmato of demad systems for meat ad fsh Tusa, eve though there s some complexty. Thus, to what extet ths creased complexty ca mprove the above result s a ope questo, whch s away from the obectve of ths research ad that every reader should apprecate. I ay case, ay estmated model should be valdated from both the ecoomcally ad statstcally pot of vew, as we have doe ths study. I ths work, we tred to start a certa le of research that wll complemet both aspects of whch had already bee treated the demad lterature. Obvously, ths research ca be mproved the future, both from the methodologcal ad the appled pot of vew. I the frst case, the estmato ad comparso mult-equato systems usg pael data s a feld that s the subect of theoretcal research, especally regard to the developmet of specfcato tests multvarate verso. From the appled pot of vew, the troducto of varables other tha the tradtoal come, prces ad demographc characterstcs ca be determat for meat ad fsh cosumpto the Tusa socety. Issues such as det qualty ad formato about the det-health are factors that fluece the demad for these products ad therefore should be troduced the future researches. Refereces Barte, A.P. (1993). Cosumer Allocato Models: Choce of Fuctoal Form. Emprcal Ecoomcs, 18, Be Kaaba, M., Dhehb, B.,& Gl, J.M. (2000). A ew framework to estmate ad detfy co- tegrated demad systems: A applcato to Tusa meat cosumpto. XXIV- IAAE Coferece. Berl (Germay). Brester, G.W.,&Wohlgeat, M.K. (1993). Correctg for Measuremet Error Food Demad Estmato. The Revew of Ecoomcs ad Statstcs 75, Deato, A.,& Muellbauer, J. (1980). A Almost Ideal Demad System. The Amerca Ecoomc Revew,70, Deato, A. (1989). Qualty, Quatty ad Spatal Varato of Prce. The Amerca Ecoomc Revew, 78, Dhehb, B.,& Gl, J.M. (1999). Demad for red meat, poultry ad fsh Tusa : A geeralzed addlog demad system. New Medt, 99, Dhehb, B., Gl, J.M. & Agulo, A. (2001). La demada de cares y pescados e Túez: u efoque dámco. Revsta Española de Estudos Egresocales y Pesqueros 190, Dhehb, B.,& Gl, J.M. (2003). Forecastg food demad Tusa uder alteratveprcg polces. Food Polcy, 28, Graca, A.,& Albsu, L.M.(1998). The demad for meat ad fsh Spa : Urba ad Rural areas. Agrcultural Ecoomcs, 19, Isttut Natoal de la Statstque (INS). (2010). Equête Natoale sur le Budget, la Cosommato et le veau de ve des méages.(report B). Tuse. Jabar, A.S. (2005). Estmato of meat demad system Jorda: a almost deal demad system. Iteratoal Joural of Cosumer Studes 29, Keller, W.J.,& Va Drel, J. (1985). Dfferetal Cosumer Demad Systems. Europea Ecoomc Revew,27, Neves, P.A. (1994). Class of Dfferetal Demad Systems. Ecoomc Letters, 44, Talaard, P.R., Va Schalkwyk, H.D.,& Alemu, Z.G. (2006). Choosg betwee the AIDS ad Rotterdam models : A meat demad aalyss case study. Agreko, 45. Thel, H. (1965). The Iformato Approach to Demad Aalyss. Ecoometrca, 33,

12 Icome, Educato, ad Age Effects o Meat ad Fsh Wlso, C.A.,& Marsh, T.L. (2005). The mpacts of demographcs ad healthformato o meat demad. Staff Paper. Departmet Of Agrcultural Ecoomcs. Perdue Uversty. 12