development plans and provide the informat .i'on on thP. socia' and cul~ tu.-at forces in the rural communit if.!5 which he,ps t.he planners ~~~ assessing the social feasibility of development measures. III. ~UANTITATIVE PlANNING PROC EDU~ES Formalized o..-quantitative planning procedur .-~s are basea on th~ use of quantitative models; the structure and equations of which aim at reproducing d part or the totality of the economic real. ities and mechanisl'ls. One can rouqh1y aist:in guish three types of rnoaels accord ­ inq to their utiliz: at.i<ill: forecasting. simu1at ion and investment anal·~ ysis models. There is no strj~t dichotomy bet~een forecasting and simutatton models. and they may often be used fa~ both purposes with onty minot'" modifications; in qeneraJ9 however. simulat ion models are more disaggregated than forecasting ones. tnv·estment analysis mod-ele; are focusseo on a sinqJe micro-ec onomic dct~vaty; thus the level o~ disaggregation hef""e is ma><i mum. In fact. the I eve I of di. saqgf'egat ion of a model is one of the det:erminant factors for the definition of dc:lt~ requir ements. but, in gener-al, because th~ realism of mathema t·-­ icaf pnJgramming models depends more than anything else on the rjchness of choice and levet of detatts incorporated in the possibil­ities. these p1dnning proceaures are more <1em.anoang than the {1) One of these documents was pYepdred for the Expert Consulta­ tion on Socio-Econorllic Tnrfi~ators for Monitoring and Evaluation of Agrari·an Reform and Rural Oevelop .ment in the Near E.asty held at Tunis in . .June 1982 .. 4 -'5 - non-quantitative pr-ocedl]res in terms of quantity and qual.it-; of the data. To htghlight the data requirements of the formalized planning procedures ·• two agric:u1tu.-a1 models will be presented here" one us~<J in project anatysis and the other one used for national plannfng. ~.!._!b~_g£Q1~£1_!!~l§_~!l!!!Y~is _~!}Q2.l~~!~!.i2!LQ!.Q9~me_!.Q.~lli 