Outline of the SOVAM

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NOT FOR QUOTATIOX WITHOUT PERKISSION OF THE AUTHOR

V. Fedorov V. Iakimets

S e p t e m b e r 1 9 8 5 V P - 8 5 - 5 7

Working Papers a r e interim r e p o r t s on work of t h e International Institute f o r Applied Systems Analysis and h a v e r e c e i v e d only lim- ited review. Views o r opinions e x p r e s s e d h e r e i n d o not neces- s a r i l y r e p r e s e n t those of t h e Institute o r of i t s National Member Organizations.

INTERXATIONAL INSTITUTE FOR APPLIED SYSTEVS ANALYSIS 2361 Laxenburg, Austria

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FORE WORD

Understanding t h e n a t u r e and dimensions of t h e world food problem and t h e policies available t o alleviate i t h a s been t h e focal point of IIASA's Food and Agriculture Program (FAP) since i t began in 1977.

National food systems are highly interdependent, and y e t t h e major policy options e x i s t at t h e national level. T h e r e f o r e , t o e x p l o r e t h e s e options, it i s n e c e s s a r y both t o develop policy models f o r national economies and t o link them t o g e t h e r by t r a d e and c a p i t a l t r a n s f e r s . Over t h e y e a r s FAP h a s , with t h e help of a network of collaborating institutions, developed and linked national policy models of twenty countries, which t o g e t h e r account f o r nearly 80 p e r c e n t of important agricultural a t t r i b u t e s such as a r e a , production, population, e x p o r t s , imports and s o on. The remaining c o u n t r i e s a r e r e p r e s e n t e d by 14 somewhat simpler models of groups of countries.

The c o u n t r i e s constituting t h e Council of Mutual Economic Assistance (CMEA) t o g e t h e r are a major influence on t h e world market. An a g g r e g a t e food and a g r i c u l t u r e model of t h e CMEA, in which t h e CMEA is t r e a t e d as one nation h a s been developed by t h e FAP, as p a r t of t h e IIASA/FAP basic linked system.

In addition, development of detailed models f o r some of t h e major nations constituting t h e CMEA w a s undertaken. The development of t h e Soviet Agricultural Model (SOVAM) w a s s t a r t e d in l a t e 1983 in collaboration with a number of institutions in t h e Soviet Union. These include t h e All- Union R e s e a r c h Institute of Cybernetics in Agriculture, t h e Computer Cen- t r e of t h e USSR Academy of Sciences, t h e All-Union Research Institute f o r Systems Studies, and t h e Central Economic Mathematical Institute.

This working p a p e r i s one of a s e r i e s of working p a p e r s documenting t h e work t h a t went into developing t h e various models of FAP. In t h i s p a p e r , V. Fedorov and V. Iakimets d e s c r i b e t h e outline of t h e SOVAM model.

Kirit S. P a r i k h Program Leader Food and Agriculture Program.

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The authors are very grateful to Cynthia Enzlberger for typing this paper.

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ABSTRACT

In this paper, t h e general structure, information flows and outline exchange and production modules of t h e

SOVAM

a r e described.

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CONTENTS

Introduction

1. Main assumptions

2. Stages of the SOVAM development

3. General structure and information flows 4. Consumption and exchange module 5. Outline of production module 6. Summary

References

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OUTLINE OF THE SOVAM V Fedorov

I.: Iakimets

Introduction

The main goal of t h e IIASA's Food and Agriculture P r o g r a m is to create a s e t of national a g r i c u l t u r a l models i n t e r a c t e d t h r o u g h t h e world market model as tool f o r understanding t h e influence of c u r r e n t and f u t u r e national policy options upon t h e international food situation f o r t h e period of 15-20 y e a r s . During t h e period from 1977 until 1984, within t h e framework of t h i s Program. and in collaboration with d i f f e r e n t national and international organizations, t h e linkage system and i t s methodological b a s e were developed. Algorithms and s o f t w a r e f o r national and international equilibrium computations were p r e p a r e d and d i f f e r e n t c o u n t r y ' s a g r i c u l t u r a l policy models of various complexity were e l a b o r a t e d . ( P a r i k h and R a b a r (1981), F i s c h e r and F r o h b e r g (1980), Keyzer and Rebelo (1982), Csaki (1982)).

The Soviet Union i s r e p r e s e n t e d now in t h e FAP system through t h e CMEA c o u n t r i e s model which h a s a g g r e g a t e d c h a r a c t e r (Csaki 1982). Unfortunately a n independent model f o r t h e USSR a g r i c u l t u r a l sector doesn't e x i s t in t h e c u r r e n t v e r s i o n of t h i s model. T h e r e f o r e w e h a v e two possibilities: to develop t h e Soviet model to b e used in a stand-alone mode or to make a disaggregation of t h e c u r r e n t CMEA countries' model up to e a c h c o u n t r y ' s submodels with a g e n e r a l a g r i c u l t u r a l policy module f o r t h e Community. W e believe t h a t t h e l a s t proposal i s t h e p r e f e r - a b l e one, however, in t h i s p a p e r w e shall not discuss how i t could b e done.

This p a p e r i s devoted only to t h e problems of t h e Soviet model construction.

Development of t h e SOViet Agricultural Model (SOVAK) w a s s t a r t e d in t h e second half of 1983. The background, conceptual framework and some of t h e sta- t i s t i c a l d a t a for t h e SOVAK are d e s c r i b e d in Iakimets (1984).

This p a p e r is mainly concerned with t h e following a s p e c t s of t h e SOVAM:

-

t h e s t r u c t u r e of t h e model and i t s information flows;

-

main s t a g e s of t h e SOVAY development;

-

outline of exchange, consumption and production modules.

1. &in assumptions

To begin t h e description of t h e g e n e r a l s t r u c t u r e and. information flows of SOVAK, we b r i e f l y r e p e a t t h e assumptions which were formulated in Iakimets 1984.

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Assumption 1

Being descriptive in n a t u r e as many of t h e FAP models are, t h e SOVAh! has t o contain t h e normative elements t o r e f l e c t t h e planned c h a r a c t e r of socialist agri- c u l t u r e development.

Assumption 2

Targeted levels, growth rates and s t r u c t u r e of output of a g r i c u l t u r a l production a r e specified f o r t h e SOVAX exogenously.

Assumption 3

Alternatives t o minimize deviations of r e a l domestic a g r i c u l t u r a l output induced mainly by weather impact from t a r g e t levels h a v e t o b e considered explicitly and have t o b e determined endogenously.

Annual t a r g e t levels of internal consumption and i t s growth rates in agricul- t u r a l and food commodities are specified exogenously.

Assumption 5

Versions f o r attainment of consumption t a r g e t s in a g r i c u l t u r a l commodities have t o b e modelled explicitly. Comparisons of t h e s e versions and selection of t h e p r e f e r a b l e one h a s t o b e envisaged endogenously.

Assumption 6

General volumes of some input r e s o u r c e s (investments, labour, f e r t i l i z e r s , e t c . ) f o r t h e a g r i c u l t u r a l s e c t o r f o r t h e period under consideration a r e specified exogenously.

Assump tion 7

Volumes of foreign t r a d e in agricultural and food commodities both f o r import and e x p o r t have t o m e e t t h e lower and u p p e r c o n s t r a i n t s given exogenously.

Assumption 8

Financial c o n s t r a i n t s f o r import and e x p o r t in a g r i c u l t u r a l and food commodi- t i e s a r e determined by a n exogenously given foreign t r a d e balance.

Assumption 9

Domestic p r o d u c e r and consumer p r i c e s f o r main a g r i c u l t u r a l and food commodities don't r e l a t e t o t h e i r world market prices. Retail p r i c e s of most goods a r e s t a b l e f o r t h e period under consideration.

2. Stages of the SOVAM development

Taking into account t h e expediency of t h e s t e p by s t e p elaboration of t h e SOVAM it is r e a s o n a b l e now t o c h a r a c t e r i z e main planned s t a g e s of this model development. W e d i s c e r n t h e following 3 stages.

First Stage

The exchange and consumption modules are developed as a n optimization model. The production module i s described by a r e g r e s s i o n t y p e model. The a g r i - c u l t u r a l policy module isn't formalized e i t h e r in t h e p a r t r e l a t e d t o exchange and consumption, o r in t h e p a r t of internal production development. (See Assumptions

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6-9). The elements describing t h e internal a g r i c u l t u r a l policy are given exogenously. Exchange, consumption and production modules of t h e SOVAN: d o not contain feedbacks. The world market p r i c e s on a g r i c u l t u r a l commodities don't influ- e n c e t h e i n t e r n a l a g r i c u l t u r a l output and i t s s t r u c t u r e . I t i s also supposed t h a t t h e allocation of r e s o u r c e inputs such as c a p i t a l , f e r t i l i z e r s , labour etc. does not depend upon t h e s e p r i c e s and t h e i r allocation will change exogenously in accor- dance t o historical d a t a analysis and s t a t i s t i c a l f o r e c a s t i n g (assumption 6).

Second Stage

Fluctuations in t h e weather and climatic changes will b e taken into consideration. At t h i s s t a g e of t h e SOVAh! development t h e s t a t i s t i c a l significance of t h e s e f a c t o r s f o r i n t e r n a l a g r i c u l t u r a l output and t r a d e flows will b e studied. The struc- t u r e of t h e production module and o t h e r modules as well as main assumptions and relations will b e assumed

to

b e similar to t h e f i r s t s t a g e .

Third

Stage

A t t h i s s t a g e t h e main e f f o r t s will b e d i r e c t e d to t h e construction of a more sophisticated version of t h e production module. I t s core will b e t h e optimization model which will r e f l e c t t h e dependence of a g r i c u l t u r a l output on national agricul- t u r a l policy options and fluctuations of world market p r i c e s . I t is supposed how- e v e r t h a t t h i s model will b e a g g r e g a t i v e and will include mainly variables which are more or less explicitly connected with e x p o r t or import of a g r i c u l t u r a l commodities. I t will n e v e r t h e l e s s b e c o n s t r u c t e d in a way t o study what kind of policies in t h e a g r i c u l t u r a l sector will allow a reduction in imports in t h e n e a r f u t u r e , while at t h e same time providing f o r admissible levels of i n t e r n a l consumption of agricul- t u r a l and food commodities.

Naturally t h e model should t a k e into account t h e main directions of t h e development of t h e USSR agro-industrial complex both in technology and economy.

Special attention will b e given t o t h e study of t h e a p p r o p r i a t e proportion between industries involved in a g r i c u l t u r a l and food production. Depending on availability of corresponding information, i t is a l s o supposed to t a k e into consideration t h e regional s t r u c t u r e of Soviet a g r i c u l t u r e .

3. General structure and information flows

The SOVAM h a s t o meet two sets of requirements. F i r s t of all t h e s e are requirements of t h e FAP Basic Linked System:

-

p r e s c r i b e d l i s t of a g g r e g a t e d a g r i c u l t u r a l commodities f o r exchange ( s e e Table 1 )

-

one y e a r time increment

-

t h e country's e x p o r t (import) f o r each commodity should b e a function of world market p r i c e s which s a t i s f i e s c e r t a i n assumptions (continuity, homo- geneity of d e g r e e z e r o )

-

_anational model should contain production, policy, exchange and consumption modules.

Specific national requirements are defined by assumptions 1-9 and c a n b e summarized in t h e following way:

-

c e n t r a l l y planned development

-

existence of t a r g e t levels for production and consumption and t h e i r growth rates according t o t h e USSR Food Program ( s e e Table 2 f o r human consumption)

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Table 1. The

F A .

Commodity Lists

No.

1 2 3 4

Aggregated Commodl ty wheat r i c e ,milled c o a r s e g r a i n s bovine and ovine meats dairy p r o d u c t s

o t h e r animal products

protein f e e d s o t h e r foods

nonfood a g r i c u l t u r e nonagriculture

Units of

Measurement N o .

lo3

^{t o n s}

103 t o n s

lo3

^tons

l o 3

^{t o n s}

lo3

^tons

f r e s h milk equivalents 103 tons

protein equivalents

l o 3

^{t o n s}

p r o t e i n equivalents million USQ 1970

millions US$1970

Disaggregated Commodl ty wheat r i c e ,milled c o a r s e g r a i n s bovine and ovine meats d a i r y p r o d u c t s

p o r k

poultry and eggs fish

p r o t e i n feeds oils and f a t s s u g a r p r o d u c t s vegetables f r u i t s and nuts coffee

cocoa, tea

and t h e i r products alcoholic b e v e r a g e s clothing f i b e r s industrial c r o p s

-

t h e model should b e based on official national s t a t i s t i c a l data.

I t should b e emphasized t h a t t h e s t r u c t u r e of t h e SOVAM h a s t o b e flexible and t o allow a f u t u r e improvement of e a c h module independently. A t p r e s e n t t h e model consists of 4 main modules (see Figure 1): production, consumption, policy and exchange. The information flows between t h e s e a r e shown on t h i s scheme.

The SOVAM policy module h a s t h r e e interconnected blocks c o n c e r n with policy decisions on production, consumption and foreign t r a d e in a g r i c u l t u r e and food commodities. The r e a s o n s f o r t h i s were described in Iakimets 1984. According t o t h e s t a t e long-term plans and guidelines f o r Soviet a g r i c u l t u r e development within t h e s e t h r e e blocks t a r g e t s , p r o p o r t i o n s and c o n s t r a i n t s have t o b e determined.

F o r instance, decisions r e g a r d i n g t h e p e r capita consumption, p r o p o r t i o n s between various consumers in e a c h commodity and growth r a t e s of i t s consumption f o r t h e period under consideration will b e specified.

Decisions concerning a g r i c u l t u r a l production include volumes and growth rates of each commodity, production and p r e s c r i b e d self-sufficiency r a t i o as tar- g e t s , and availability of various input r e s o u r c e s as constraints (labour, a c r e a g e , c a p i t a l investments, c a p a c i t i e s and s o on) as well as p r e s c r i b e d p r o p o r t i o n s of t h e i r utilization f o r d i f f e r e n t commodities.

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-

5

-

Table 2.

Per

capita annual consumption of foodstuffs (in kg)

(planned t a r g e t s ) Meat and meat p r o d u c t s

(including animal fats and byproducts)

Kilk and d a i r y p r o d u c t s (in terms of milk)

Eggs (pieces)

Fish and fish p r o d u c t s Vegetable oil

Potatoes

Vegetables and melons F r u i t s and b e r r i e s

Breads and c e r e a l p r o d u c t s Sugar8**

Source: N. A. Tikhonov, p. 180

=

The USSR economy for the period 1922-1982, p. 73

==

K. Bogolyubov, p. 113

===

The USSR economy in 1980, p. 405

Decisions concerning a g r i c u l t u r a l foreign t r a d e determine t h e value of f o r e i g n t r a d e t u r n o v e r as a t a r g e t and e x p o r t r e v e n u e and import budget as con- s t r a i n t s . Information o n them have t o b e used in modules 11, 111 and IV of t h e SOVAM

( s e e double a r r o w s o n t h e scheme).

According to t h i s information t h e planned consumption f o r e a c h commodity is calculated in t h e consumption modules. These r e s u l t s as w e l l as d a t a on e a c h commodity's i n t e r n a l production in t h e previous period (t-1) and t h e information concerning t a r g e t s , p r o p o r t i o n s and c o n s t r a i n t s f o r a g r i c u l t u r a l foreign t r a d e , are delivered to t h e exchange module. Within t h i s module t h e corresponding optimization problem i s solved a t e v e r y s t a g e of t h e i t e r a t i v e p r o c e d u r e of d e t e r - mining t h e equilibrium world market. In o t h e r words t h e SOVAM w i L L react t h r o u g h t h e exchange module on changing world p r i c e s and d e l i v e r t h e d a t a a b o u t i t s e x p o r t / i m p o r t volumes to t h e global system. When equilibrium i s a p p r o a c h e d , t h e value of consumption corresponding t o t h e equilibrium point is calculated with t h e e x c h a n g e module and transmitted t o blocks I and IV to make decisions on t a r g e t s , c o n s t r a i n t s and p r o p o r t i o n s in all t h r e e blocks of t h e policy module. These decisions are inputs of t h e production module which works o u t t h e production volumes f o r t h e n e x t period.

I t should b e noted t h a t within t h e SOVAM t h e s p e c i a l submodule f o r calculation of a number of o t h e r endogenous v a r i a b l e s i s envisaged (it is not shown in Figure 1 ) . These will include s e v e r a l g e n e r a l indicators such as g e n e r a l domestic pro- d u c t , investments, volume of f e r t i l i z e r s e t c . , and s e v e r a l sectorwise p a r a m e t e r s such as f e e d , human consumption, a c r e a g e , yields and so on.

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- 6 -

Figure 1:

The SOVAM

general structure and information flows

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4. Consumption and exchange module

Let I be t h e index s e t of aggregated a g r i c u l t u r a l c r o p s commodities; i r

I;

J is t h e index s e t of aggregated livestock commodities, j r

J,

and

I U J = I,,

J

I, =

n

-

1.

According t o t h e previous section, t h e t a r g e t s dL(t)

=

( d L 1 ( ~ ) ,

. . ..

, d L n -l(t))T f o r human consumptior. of commodities in y e a r t are given exogenously. H e r e "T"

s t a n d s f o r transposition. It is c l e a r t h a t

where: K ( t ) i s population in y e a r t given by some s c e n a r i o s , v(t)

=

(vl(t),

. .. .

, vn -l(t))T i s t h e v e c t o r of t h e p e r c a p i t a annual consumption values of which f o r t h e period under consideration c a n b e calculated f o r example with t h e help of l i n e a r approximation:

I

Here values of T, v(o) and v(T) are t a k e n from national s t a t i s t i c s and t a r g e t s determined in t h e USSR Food Program (see Table 2 f o r o b s e r v e d changes of r e a l p e r c a p i t a consumption of main s t a p l e foodstuffs in t h e Soviet Union f o r t h e p e r i o d 1950 t o 1980 and t a r g e t s for 1990). These t a r g e t s f o r 1990 were determined on t h e basis of scientifically developed s t a n d a r d s . Hence i t is r e a s o n a b l e t o u s e t h e s e t a r g e t values t o fix v(T) for T

=

1990. The value of v(o) can b e t a k e n f o r example equal t o ~ ( 1 9 8 0 ) .

According t o t h e f i r s t s t a g e of t h e SOVAX development, w e suppose t o imple- ment exchange module as t h e following optimization problem:

s u b j e c t to:

Balance of commodities utilization

d ( t )

=

~ ( t ) y(t

-

^{1 )}

+

^z-(t)

-

z + ( t )

-

^w(t)

Balance of f e e d s and livestock commodities dT(t) p k ( t )

-

wT(t)

-

-yk

=

9, k

=

1 , 2 . Value of a g r i c u l t u r a l e x p o r t

E(t)

=

pT(t) z + ( t ) ²~ + ( t ) Value of a g r i c u l t u r a l import I ( t )

=

^pT(t)

.

^z-(t)

^s

^R-(t)

Low and u p p e r bounds f o r volumes of e x p o r t z + ( t )

s

z + ( t )

s

E+(t)

-

Low and u p p e r bounds f o r volumes of import z-(t)

s

2-(t)

s

2 3 )

-

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Weights o l ( t ) and +(t) are given exogenously. Matrix A (t) d e s c r i b e s t h e signifi- c a n c e of commodities and t h e i r replaceability.

The volumes of i n t e r n a l production of c r o p and livestock commodities y(t) are determined in t h e production module. Components of

z + ( t ) and z-(t) are volumes of e x p o r t and import of a g r i c u l t u r a l commodities;

d (t) are t h e calculated volumes of human consumption of commodities;

E

(t) i s revenue f r o m e x p o r t of a g r i c u l t u r a l commodities;

I (t) i s expenditures for import of a g r i c u l t u r a l commodities;

R + ( ~ ) , R - ( t ) are correspondingly c o n s t r a i n t s on h a r d c u r r e n c y used f o r e x p o r t and import.

Components of ~ ( t ) , z(t) are low and u p p e r c o n s t r a i n t s on volumes of e x p o r t and import of commodities, f o r describing f o r example long-term t r a d e agreements.

Coefficients pk(t) determine t h e amount of k-th s u b s t a n c e needed t o p r o d u c e 1 unit of livestock commodity (k

=

1 is r e l a t e d to feed units and k

=

2 to protein) and coefficients 7k shows t h e value of k-th substance in 1 unit of c r o p commodities.

The components of o(t) are s h a r e s of internal outputs used f o r human consumption.

Vector w(t) d e s c r i b e s t h e consumption of t h e c r o p by livestock population. There- f o r e i t has non z e r o components mainly f o r c r o p commodities.

Including of w(t) i n t o t h e balance equation i s v e r y important f o r t h e determi- nation of import v a l u e s f o r c r o p commodities. In t h i s v e r s i o n of t h e SOVAM exchange module, t h e s e values will b e given exogenously according to d i f f e r e n t scenarios. T h e r e e x i s t s a number of proposals f o r t h e improvement of f e e d production in t h e Soviet Union. The description of some of t h e s e proposals o n e c a n find in Iakimets (1984), s e c t i o n 3.5. The abovementioned s c e n a r i o s will c o r r e l a t e with them. T h e r e are two ways of constructing s c e n a r i o s f o r w(t): by exogenously calculating t h e time s e r i e s of w(t) corresponding to s e l e c t e d proposals f o r t h e whole period u n d e r consideration o r by t h e following equation:

and values of c ( t ) given exogenously are s h a r e s of c r o p commodities used t o feed livestock.

The component of t h e v e c t o r i ( t )

=

d(?(t), i?-(t)) c a n b e called "attainable consumptions". The a b o v e used optimality c r i t e r i o n i s t h e simpliest one.

S t r i c t l y speaking t h e c h o i c e of t h e optimality c r i t e r i a should b e defined by decision makers. F o r i n s t a n c e taking into account assumption 3 one can use t h e following c r i t e r i o n :

min F(d) d

where

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5. Outline of the production module

In this section t h e s h o r t description of t h e a g r i c u l t u r e production module is given. The t w o principally different a p p r o a c h e s are considered. The f i r s t one is based on t h e assumption t h a t international t r a d e does not influence t h e s t r u c t u r e of Soviet a g r i c u l t u r e production. The second one assumes t h e e x i s t e n c e of feedbacks between e x c h a n g e and production modules. These f e e d b a c k s drastically i n c r e a s e t h e complexity of t h e model (both methodologically and technically).

Presumably t h e latter a p p r o a c h will b e used only in t h e final s t a g e of t h e model- ling.

The preliminary s t a t i s t i c a l analysis does not confirm t h e e x i s t e n c e of any significant c o r r e l a t i o n between export-import d a t a and d a t a describing t h e s t r u c t u r e of a g r i c u l t u r e sector.

In what follows below only t h e f i r s t a p p r o a c h will b e considered and i t s imple- mentation on t h e basis of s t a t i s t i c a l approximation. Usually s t a t i s t i c a l methods can b e a p p r o p r i a t e l y used when some kind of "stability" is o b s e r v e d in d a t a on t h e development of t h e o b j e c t under investigation. In o u r case t h i s stability r e a l l y i s confirmed both by s t a t i s t i c a l d a t a and by analysis of s t r u c t u r a l development of t h e a g r i c u l t u r a l sector. At p r e s e n t f o r t h e production module t h e mixed regression- autoregression models are used:

yt

=

F ( I P , ~ )

+ r

^{y t - ~}

⁺

^ct

.

⁽¹¹⁾

where yt is a v e c t o r t h e components of which c o r r e s p o n d to volumes of production of different commodities, t h e v e c t o r F ( 6 , t ) i s a set of given functions, 6 and

I-

are matrices containing unknown p a r a m e t e r s , t i s time, t h e v e c t o r s ct d e s c r i b e s t h e random errors.

Usually F(6.t) approximates long-term t r e n d s , t h e second summond r e f l e c t s t h e fluctuations with significant deterministic components, rt accumulates t h e random weather fluctuations and some nonsignificant f a c t o r s , which f o r instance can not b e approximated in a deterministic way because of l a c k of information.

I t should b e pointed out t h a t v e c t o r yt can contain a number component which c o r r e s p o n d s to t h e same product. It happens when o n e n e e d s t o work with a n autoregression of t h e second or h i g h e r o r d e r .

At p r e s e n t t h e random e r r o r s are suggested t o b e independent with z e r o means:

where btt, i s K r o n e c k e r ' s symbol and D i s variance-convariance matrix.

The nonapriculture sector is modelled h e r e independently of (11) with t h e help of traditional Cobb-Douglas function:

where ynt is t h e volume of nonagricultural production (only o n e product!) K(t) i s capital, L(t) i s l a b o r f o r c e , ~ ( t ) r e f l e c t s t h e technical p r o g r e s s , and et i s a random value with z e r o mean a n d E(et, et,)

=

^a*bttr. The main r e a s o n f o r t h e isolating of ynt i s t h e conjunction of t h e S O V A M with t h e FAP system of models.

The description of t h e SOVAM production module as a n optimization model will b e given in t h e n e x t p a p e r .

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6. Summary

The g e n e r a l s t r u c t u r e , information flows, outline of e x c h a n g e and consumption module as well as p r o d u c t i o n f o r t h e f i r s t s t a g e of t h e SOVAM development w e r e d e s c r i b e d in t h i s p a p e r . The n e x t p a p e r will contain t h e m o r e detailed d e s c r i p t i o n of both modules a n d f i r s t r e s u l t s of estimation of c o r r e s p o n d i n g functions parame- ters.

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References

Bogolyubov, K . (1983). Development of t h e Agrarian S e c t o r in t h e USSR. Novosti P r e s s Agency Publishing House, M o s c o ~ .

Csaki, C. (1982). Long-term p r o s p e c t s for Agricultural Development in t h e Euro- pean CMEA Countries, including t h e Soviet Union. RR-82-25, IIASA, Laxenburg F i s c h e r , G . and K . F r o h b e r g (1980). Simplified National Models

-

t h e condensed version of t h e Food a n d Agriculture Model System of t h e IIASA. WP-80-056, IIASA, Laxenburg.

Iakimets, V. (1984). Background and requirements for t h e SOVAM: Soviet Agricul- t u r a l Model. WP-84-97 IIASA, Laxenburg.

Keyzer, M. and Rebelo J. (1982). A Description of t h e S o f t w a r e of t h e IIASA/SOW Food and Agriculture Model. SOW 82-16, F r e e University of Amsterdam, C e n t e r for World Food Studies.

Keyzer,

M .

The International Linkage of Open Exchange Economies (forthcoming) P a r i k h , K. and F. R a b a r (eds.) (1981). Food for A l l in a Sustainable World: The

IIASA Food and Agriculture Program, SR-81-2. IIASA, Laxenburg.

Tikhonov, N.A. (1983). Soviet Economy: Achievements, Problems, P r o s p e c t s . Novosti P r e s s Agency Publishing House, Moscow.

The USSR Economy in 1980, S t a t i s t i c a l Yearbook (1981). C e n t r a l S t a t i s t i c a l Board Publishing House, Moscow (in Russian).

The USSR Economy for t h e P e r i o d 1922-1982, Anniversary S t a t i s t i c a l Yearbook (1982). C e n t r a l S t a t i s t i c a l Board Publishing House, Moscow (in Russian)