The determinants of fertility and child survival in the Nepal Terai

The c o n c l u s i o n s and views e x p r e s s e d i n tk's paper a r e t h o s e of t h e a u t h o r and do not n e c e s s a r i l y r e f l e c t t h o s e of t h e World Bank Group. The paper is a ( d r a f t f o r discussion; - p - l e a s e do n o t c i t e w i t h o u t t h e a u t h o r ' s permi.;sion. P o p u l a t i o n and Human Resources D i v i s i o n D i s c u s s i o n Paper No. 81- 34 THE DETERMINANTS OF FERTILITY AND CHILD SURVIVAL I N THE NEPAL TERAI J u l y 1981 Prepared by: Susan H. Cochrane Prepared f o r : . * Reseerch P r o j e c t 671-49, "Education and Rural D e v e l o ~ m e n t i n Neual and The World Bank Washington, D.C. 20433 U.S.A.  THE DETEWIXANTS OF FERTILITY AND CHILD SURVIVAL I N THE NEPAL TERAI Susan H. Cochrane ABSTRACT The households in our sample i n t h e Bara and Rautahat d i s t r i c t s of t h e Nepal T e r a i have lower f e r t i l i t y t h a n they d e s i r e i n most c a s e s . T h i s r e s u l t s from long b i r t h i n t e r v a l s and h i g h c h i l d m o r t a l i t y . As a consequence, t h e r e i s l i t t l e demand f o r c o n t r a c e p t i o n . B i o l o g i c a l f a c t o r s of age and f e c u n d i t y a r e t h e major d e t e r m i n a n t s of c h i l d r e n e v e r born i n t h i s sample. The o n l y b e h a v i o r a l f a c t o r a f f e c t i n g f e r t i l i t y i s a g e of c o h a b i t a t i o n which is determined t o some e x t e n t by p a r e n t a l l a n d ownership and w i f e ' s i n t e l l e c t u a l a b i l i t y , b u t t o a much l a r g e r e x t e n t by age of menarche. In addition, f e r t i l i t y is s i g n i f i c a n t l y related t o t h e p r o p o r t i o n of c h i l d r e n s u r v i v i n g . C u r r e n t f e r t i l i t y a s measured by t h e l a s t open i n t e r v a l i s d e t e r m i t e d by age and t h e l e n z t h of b r e a s t f l e d i n g which is i n t u r n determined by t h e s u r v i v a l of t h e l a s t c h i l d . Thus f e r t i l i t y and s u r v i v a l a r e r e l a t e d b o t h over t h e e n t i r e r e p r o d u c t i v e span and i n t h e c u r r e n t p e r i o d . The e v i d e n c e s u g g e s t s t h a t i n t h i s sample s u r v i v a l a f f e c t s f e r t i l t y and n o t t h e converse, but t h i s c o n c l u s i o n must be somewhat s p e c u l a t i v e g i v e n t h e r e l a t i v e l y small sample involved and t h e c o m p l e x i t i e s i n v o l v e d i n modeling mortality. Our d a t a s u g g e s t t h a t t h e p r o p o r t i o n of c h i l d r e n s u r v i v i n g depends on exposure and t h e husband's l i t e r a c y . The s u r v i v a l of t h e most r e c e n t c h i l d depends on exposure and t h e s u r v i v a l of p r e v i o u s c h i l d r e n which i n t u r n i s dependent on t h e husband's l i t e r a c y and i s m a r g i n a l l y r e l a t e d t o t h e s e x of t h e c h i l d . These r e s u l t s , however, a r e based on a sample of about 500 households f o r which r e l e v a n t d a t a were a v a i l a b l e and must be c o n s i d e r e d a s tentative. 8 1 L Our major c o n c l u s i o n is t h a t f e r t i l i t y i n t h i s a r e a is determined p r i m a r i l y by b i o l o g i c a l f a c t o r s . While improved e d u c a t i o n might r a i s e t h e a g e of marriage and c o h a b i t a t i o n a s well_ a s reduce t h e d e s i r e d number of c h i l d r e n , t h e most i m p o r t a n t way t o reduce f e f t i l i t y both i n t h e s h o r t and long r u n i s t o reduce m o r t a l i t y . ~ n f o r t u n a t e l ~ 2 t h e d a t a p r o v i d e l i t t l e i n s i g h t i n t o how t h i s might be done except through improved e d u c a t i o n s i n c e p o l i c y v a r i a b l e s r e l e v a n t t o m o r t a l i t y were n o t i n c l u d e d i n t h e d a t a , a s m o r t a l i t y was n o t a - f o c u s of the o r i g i n a l r e s e a r c h p l a n p b u t only immerged a s c r i t i c a l i n t h e analysis.  Models of f e r t i l i t y d e t e r m i n a t i o n have t-aken s e v e r a l forms. They d i f f e r i n s e v e r a l dimensions : t h e l e v e l of a n a l y s i s ( a g g r e g a t e o r i n d i v i d u a l ) , t h e r e f e r e n c e p e r i o d ( c u r r e n t o r l i f e t i m e ) and t h e emphasis on s u p p l y o r demand f a c t o r s . Most economic models have been used t o e x p l a i n individual"^ lifetime f e r t i l i t y . I n a d d i t i o n , most of t h e economic work u n t i l r e c e n t l y h a s focused on d e t e r m i n a n t s of t h e demand f o r c h i l d r e n . There is i n c r e a s i n g e v i d e n c e , however, t h a t i n many p a r t s of t h e world t h e b i o l o g i c a l supply o f l i v i n g c h i l d r e n is t h e binding c o n s t r a i n t r a t h e r t h a n t h e demand f o r c h i l d r e n . There i s a l s o some e v i d e n c e t h a t c u r r e n t f e r t i l i t y i s more amenable t o economic analysis than i s l i f e t i m e f e r t i l i t y . I n t h i s paper we s h a l l b r i e f l y e x p l a i n a l i f e t i m e model of f e r t i l i t y which i n c o r p o r a t e s b o t h supply and demand e l e m e n t s and t h e n e x p l o r e t h e s u p p l y and demand c o n s t r a i n t s u s i n g d a t a from t h e T e r a i Development Survey. Then we s h a l l e x p l o r e t h e c u r r e n t f e r t i l i t y model w i t h t h e same d a t a s e t . I n t h e l a s t p o r t i o n of t h e paper we s h a l l a n a l y z e t h e d e t e r m i n a n t s of c h i l d m o r t a l i t y and e x p l o r e t h e r e l a t i o n s h i p between m o r t a l i t y and f e r t i l i t y . The d e t e r m i n a n t s of l i f e t i m e o r completed f e r t i l i t y have been analyzed from s e v e r a l p e r s p e c t i v e s . The f i r s t economic models of f e r t i l i t y were s i m p l e e x t e n s i o n s of demand t h e o r y , a-nd a c t u a l f e r t i l i t y i n most i n s t a n c e s was equated w i t h t h e demand f o r c h i l d r e n . l ~ h e s e models a r e u n a c c e p t a b l e where * I would l i k e t o thank Kalpana Nandwani f o r h e r c a r e f u l and c r e a t i v e research assistance. I would a l s o l i k e t o thank Rajendra S h r e s t h a of Bew ERA f o r h i s comments and s u g g e s t i o n s on an e a r l i e r d r a f t of t h e  unif o m . T h e r e f o r e , t h i s s i m p l e approach i s p a r titularly i n a p p r o p r i a t e f o r developing c o u n t r i e s . E a s t e r l i n h a s developed a more comprehensive approach ( E a s t e r l i n , 1979). He h y p o t h e s i z e s that a c t u a l f e r t i l i t y , Co, i s determined by t h e b i o l o g i c a l s u p p l y of c h i l d r e n , Cs, t h e demand f o r c h i l d r e n , Cd , and the c o s t of s e r t i l i t y r e g u l a t i o n . These f a c t o r s i n t e r a c t s o t h a t d u r i u g t h e c o u r s e of development ( o r a c r o s s socioeconomic g r o u p s ) f e r t i l i t y h a s t h e p a t t e r n i l l u s t r a t e d i n F i g u r e 1. A t low l e v e l s of income o r development, t h e demand f o r c h i l d r e n exceeds t h e s u p p l y of l i v i n g c h i l d r e n ( S t a g e I ) . During t h e c o u r s e of development t h e demand f o r c h i l d r e n d e c r e a s e s and t h e s u p p l y of s u r v i v i n g c h i l d r e n i n c r e a s e s due t o improved c h i l d s u r v i v a l and p e r h a p s increased fecundity. A t some p o i n t t n e s u p p l y o f l i v i n g c h i l d r e n b e g i n s t o exceed t h e demand, b u t t h e c o s t s of r e g u l a t i n g f e r t i l i t y a r e s o high t h a t no c o n t r a c e p t i o n i s used ( S t a g e 1 1 ) . As e x c e s s s u p p l y i n c r e a s e s , c o u p l e s b e g l n t o a d o p t c o n t r a c e p t i o n ( S t a g e 111). E v e n t u a l l y when c o n t r a c e p t i v e c o s t s be- come v e r y low p e o p l e have o n l y t h e number of c h i l d r e n t h e y demand ( S t a g e I \ / ) . Our sample i n t h e T e r a i is p r i m a r i l y i n S t a g e I, b u t t h e s t a g e d i f f e r s somewhat f o r men and women. T h i s 'is i l l u s t r a t e d i n F i g u r e 2 where t h e a v e r a g e d e s i r e d number of c h i l d r e n f o r husbands and wives i s p l o t t e d a g a i n s t - - t h e w i f e ' s age. Husbands d e s i r e fewer c h i l d r e n t h a n t h e i r wives a t a l l ages. 'I - - These d e s i r e s c a n be compared LO t h e number of c h i l d r e n e v e r b o r n and s u r y i v - ) ing. On t h e a v e r a g e a t nb a g e do women have a s many s u r v i v i n g c h i l d r e n a s m t h e y would l i k e . That i s , they a r e a l l i n S t a g e I. On t h e o t h e r hand, m a l e s o v e r 35 have, o n t h e a v e r a g e , a s many s u r v i v i n g c h i l d r e n a s t h e y would l i k e ,  Number of children A Natural fertility -Source: Richard Easterlin. Robert A. Pollack. and hiichacl L. Wachta, "To- ward a More General Economic \lode1 of Fertility Determination: Endogenous Preference and Natural Fertility" (presented at the National Bureau of Economic Racarch Conference on Economic and Demographic Change in Las Developed Countries. September 3&odober 2, 1976, Philadelphia, processed). 'L 0'9 O'S O'f O'C 0'2 0'1 0'0 o SAOH ONB SJOM '35 '03% b u t i n g e n e r a l c o n t r a c e p t i v e s a r e n o t used. That i s , t h e y a r e g e n e r a l l y i n Stage 11. These a v e r a g e f i g u r e s on c h i l d r e n d e s i r e d and s u r v i v i n g c o n c e a l a n enormous amount. F i r s t , they conceal the f a c t t h a t parents a r e not i n d i f f e r e n t t o t h e sex of t h e i r c h i l d r e n . Both men and women i n the sample p r e f e r sons. F i g u r e 3 shows t h a t on t h e a v e r a g e a t no age do husbands o r wives have a s many l i v i n g s o n s a s t h e y would l i k e . This e x p l a i n s i n p a r t why husband who have a l l t h e " c h i l d r e n " they would want on t h e average may n o t wish t o c e a s e reproducing. The d a t a on a v e r a g e s a l s o c o n c e a l t h e v a r i a t i o n s around t h e a v e r a g e values. A n a l y s i s of i n d i v i d u a l ( r a t h e r t h a n s v e r a g e ) d a c a shows t h a t ' f o r only 29 of 471 c o u p l e s do both husbands and wives h a r e a l l t h e c h i l d r e n they want. An a d d i t i o n a l 56 wives and 98 husbands have a l l t h e c h i l d r e n they want, bus t h e i r spouses want a d d i t i o n a l c h i i d r e n . T h e r e f o r e , t h e r e a r e only 29 c o u p l e s who c a n be c o n s i d e r e d t o b e unambiguously i n S t a g e 11. This i m p l i e s t h a t f e r t i l i t y i n our sample approximates n a t u r a l f e r t i l i t y and t h u s depends on exposure t o c h i l d b e a r i n g and f e c u n d i t y per y e a r of marriage a s w e l l a s c h i l d s u r v i v a l . Therefore, i n our a n a l y s i s of l i f e t i m e f e r t i l i t y w e s h a l l examine t h e d e t e r m i n a n t s of age of marriage, f e c u n d i t y ( t o t h e e x t e n t i t can be measured), and how a l l of t h e & determine t h e number of c h i l d r e n e v e r born. We s h a l l a l s o examine t h e d e t e r n i n a n t s of c h i l d survival. The Determinants of Children Ever Born - Before proceeding t o e x a m i v t h e d e t e r m i n a n t s of c h i l d r e n e v e r born I i n t h i s sample, i t should be s t r e s s e d t h a t economists have developed very l i t t l e theory about what d e t e r n i n e s n a t u r a l f e r t i l i t y . Some work has been done about d e t e r m i n a n t s of f e r t i l i t y i n t h i s environment, b u t i t has been more a n a t t e n p t t o account f o r the amount of v a r i a t i o n i n a g g r e g a t e f e r t i l i t y of m a r r i a g e , e t c .--r a t h e r t h a n a n a t tempt t o e x p l a i n i n d i v i d u a l behavior (Congaarts,l979). 1/ I n our a n a l y s i s we e x p l o r e t h e r e l a t i o n s h i p between background var'ables ( c h a r a c t e r i s t i c s of p a r e n t a l household such a s p a r e n t a l l i t e r a c y , landownership, e t c . ) , individual's i n t e l l e c t u a l characteristics (modernity, l i t e r a c y , and i n t e l l e c t u a ; a b i l i t y ) , i n d i v i d u a l ' s age, and location. These v a r i a b l e s were used i n a r e c u r s i v e system t o d e t e r m i n e what f a c t o r s a r e a s s o c i a t e d w i t h age a t menarche, a g e of m a r r i a g e , and f i r s t b i r t h interval. The e f f e c t of t h e s e v a r i a b l e s on cY-ildren e v e r born a r e t h e n analyzed. --- The Hypotheses (1) P a r e n t a l c h a r a c t e r i s t i c s a f f e c t i n t e l l e c t u a l development i n such a way t h a t n o r e l i t e r a t e , r i c h e r p a r e n t s have c h i l d r e n who a r e more l i k e l y t o be l i c e r a t e . (2) The l i t e r a c y of p a r e n t s w i l l d e t e r m i n e t h e c h a r a c t e r i s t i c s of t h e mates s e l e c t e d f o r t h e i r c h i l d r e n and w i l l a f f e c t t h e age of marriage o r c o h a b i t a t ' on. (3) P a r e n t a l w e a l t h w i l l ' a t f e c t t h e a g e of menarche a s ihown in a v a r i e t y of s t u d i e s . (4) Age of k e n a r c h e w i l l a f f e c t t h e a g e of c o h a b i t a t i o n . This 3 - might a l s o be a f f e c t e d by o t h e r v a r i a b l e s such a s p a r e n t a l * - l i t e r a b p , spouse s c h o o l i n g o r i n t e l l e c t u a l c h a r a c t e r i s t i c s . - 11 E a s t e r l i n and Crimmins a r e develcging a model of t h e d e t e r m i n a n t s of n a t u r a l f e r t i l i t y a t t h e i n d i v i d u a l l e v e l which they a r e t e s t i n g w i t h d a t a from S r i Lanka and Colombia ( E a s t e r l i n and Crimmins, 1981).  ----- - FOR THE SAMPLES US 3 , I N REGRESSION ANALYSES (Number i n p a r e n t h e s e s i s f o r t h e sample w i t h p a r e n t a l landownership) Standard Variable V a r i a b l e Name Mean Deviation AFLH Age a t f i r s t c o h a b i t a t i o n AFP Age a t menarche 13.94 1.44 (14.02) (1.52) CEB Children ever born 3.81 2.10 (4.00) (2.16) DIST District l=Bara; 2=Rautahat 1.47 0.50 (1.46) (0.50) DUR Years s i n c e s t a r t e d l i v i n g w i t h 17.78 9.24 husband (18.51) (8.87) FBI First birth interval HFL I T Is husband's f a t h e r l i t e r a r e ? 0.12 0.32 1 = y e s ; 0 = no (0.13) (0.34) HLIT Is husband l i t e r a t e ? 1 = y e s ; 0 = no , kDLO Husband's f a t h z r 's landownership a ( i n bighas) (4.31) (7.16) PCS P r o p o r t i o n of c h i l d r e n s u r v i v i n g 0.75 0.28 (0.73) (0.30) KAGE Wife " s age WFLIT Is w i f e ' s f a t h e r l i t e r a t e ? 1 = y e s ; 0 = no 0.12 (0.12) - E 0.32 (0.32) WPLO Wife " s f a t h e r ' s landownership ( i n bighas ) (3.59) (7.91) kXPM Wife's Ravenos s c o r e 11.10 3.10 (11.18) (3.05) Variable V a r i a b l e &me Mean Deviation SAMPLE 2 BFLC Length of l a c t a t i o n of l a s t c h i l d 22.00 17.36 ( i n months) DIST M s t r i c t l=Bara; 2aRautahat 1.48 0.50 WCW k m b e r of a d d i t i o n a l c h i l d r e n wanted by husband HFLIT Is husband's f a t h e r l i t e r a t e ? 1 = yes; 0 = no HLIT Is husband l i t e r a t e ? 1 = yes; 2 = no k s b a n d ' s modernity s c o r e - [0,13] k m b e r of c o n t r a c e p t i v e methods known by husband - [0,5] Husband' s Raven's score W as husband v i s i t e d by t h e f a m i l y planning worker? 1 = yes; 2 = no HWS Fusband' s y e a r s of schooling LLO Length of l a s t open b i r t h i n t e r v a l ( i n months) NSC %mber of s u r v i v i n g c h i l d r e n SLC Is t h e l a s t chi1,d s t i l l a l i v e ? . 1 = yes; 0 no WACW k m b e r of a d d i t i o n a l c h i l d r e n wanted -by i wife 2.51 2.47 WA CE ' % i f e 8 s age ( i n y e a r s ) 28.81 5.89 MOD Q * Wife's modernity s c o r e - [3,131 4.57 1.89 m WMK k m b e r of c o n t r a c e p t i v e methods known by w i f e - [0,5 ] 1.77 1.31 ram Wife's Raven's s c o r e 11.04 3.14 WVF P Was w i f e v i s i t e d by t h e f a m i l y planning worker? 1 = y s ; 2 = no 1.83 3.38 WWS Wife's y e a r s of schooling 0.03 0.38  FOR THE DETERMINANTS OF LIFETIME FERTILITY FOR A SAMPLE OF 305 WOMEN I N THEIR FIRST M I A G E [t=values i n parentheses; Beta values i n brackets] AFP = 12.54 + 0.97 [0.33] DIST (6.03) AFLH = 8.29 + 0 . 5 0 [0.35] AF'P + 0.04 [O.11] HPLO ~i' = 0.14 (6.62) (2.14) CEB = -2.72 + 0.50 [2.39] WAGE - 0.01 [1.84] WAGESQ (7.38) (5.68) -0.27 [0.27] AFLH - 0.02 [0.23] FBI (6.43) (5.89) -0.74 [0.09: PCS - .02 [0.07] HPLO g2 = 0.51 (2.23) (1.73)  FOR THE DETERMINANTS OF LIFETIME FERTILITY FOR A SAMPLE OF 451 WOMEN I N THEIR FIRST MARRIAGE [ t v a l u e s i n parentheses; Beta v a l u e s i n brackets] WRPM = 10.90 + 1.76 [0.18] HFLIT (3.31) MP = 1 2 . 4 7 + 1.01 [ 0 . 3 5 ] DIST (7.86) MLH = 6.41 + 0.08 [0,.12] WWM + 0.58 [0.40] AFP z2 = 0.15 (2.74) (9.60) CEB = -2.88 + 0.58 [ 2 . 5 2 ] WAGE - 0.01 [1.93] WAGESQ (9.88) (7.57) -0.26 [ 0 . 2 6 ] AFLH ( 7 -89) - 0.02 [0.21] F B I (6.47) E~ = 0.53 -0.79 [0.11] PCS (3.22) a g e of c o h a b i t a t i o n . & a i n t h i s i s second t o t h e b i o l o g i c a l e f f e c t b u t i t i s highly significant. I n b o t h samples wmen's i n t e l l e c t u a l a b i l i t y i s p o s i t i v e l y - r e l a t e d t o h e r husband's f a t h e r ' s l i t e r a c y . e susdect t h a t i f our t e s t s W of a b i l i t y g i v e meaningful m e a s u r e s of i n n a t e a b i l i t y , t h e n t h e f a t h e r s - i n - l a w t h a t a r e l i t e r a t e select d a u g h t e r s i n - l a w who a r e b r i g h t e r . e do n o t t h i n k W f a t h e r ' s l i t e r a c y o r daughter-in-law's a b i l i t y a r e r e f l e c t i n g c a s t e because w e e l i m i n a t e d t h e two h i g h e r c a s t e g r o u p s s i n c e t h e y were t o o few i n number t o analyze s e p a r a t e l y , but s u f f i c i e n t l y d i f f e r e n t t o complicate t h e a n a l y s i s of t h e r e s t of t h e sample. Theref o r e , t h e husband' s f a t h e r ' s l i t e r a c y and w i f e ' s i n t e l l e c t u a l a b i l i t y a r e a s s o c i a t e d w i t h lower f e r t i l i t y i n d i r e c t l y through l a t e r a g e a t cohabitation. Landownership d e l a y s c o h a b i t a t i o n and h a s a more d i r e c t e f f e c t t o lower f e r t i l i t y . R a t h e r unexpected1 y , household landowner s h i p d o e s n o t i n c r e a s e f e c u n d i t y a s m i g h t be e x p e c t e d ( a s measured by t h e f i r s t 1 birth interval) -1 by improving h e a l t h . The l a s t v a r i a b l ? t h a t p l a y s a s i g - n i f i c a n t r o l e i s c h i l d survival. The h i g h e r t h e p r o p o r t i o n of c h i l d r e n s u r v i v i n g t h e l o w e r t h e number of c h i l d r e n e v e r born. Z h i s v a r i a b l e wi.11 be examined more f u l l y l a t e r i n t h e paper. L CURREhl' FERTILITY While t h e e x p l a n a t o r y power of t h e e q u a t i o n f o r c h i l d r e n e v e r b o r n i s v e r y h i g h f o r a m i c r o d a t a s e t ( . 4 7 and .52 r e s p e c t i v e l y f o r t h e * 1 -1 l h e r e s u l t s f o r f i r s t b i r t h i n t e r v a l d i f f e r by s p e c i f i c a t i o n . No s i n g l e v a r i a b l e a l o n e i s s i g n i f i c a n t l y r e l a t e d t o FBI i n e i t h e r sample. How- e v e r , when b o t h a g e a t c o h a b i t a t i o n ( M L H ) and t h e d i f f e r e n c e between t h a t a g e and a g e of menses a r e i n c l u d e d , AFLH i s m a r g i n a l l y s i g n i f i c a n t i n t h e s m a l l sample ( p o s i t i v e ) . lhis would s u g g e s t t h e t long FBI's r e s u l t i n s i g n i f i c a n t p a r t from a d o l e s c e n t s t e r i l i t y .  --- OF THE LAST BIRTH INTERVAL FOR FECUND WOMEN I N THEIR FIRST MARRIAGE [ t v a l u e s i n p a r e n t h e s e s ; Beta v a l u e s i n b r a c k e t s ] 421 WMOD = 4.42 + 0.60 [0.13] HLIT + 0.46 [0.09] WYRS (2.76) (1.94) 373 HMOD = 4.94 + 0.26 [0.39] HYRS + 0.69 [O.11] HFLIT + 0.05[0.10]HRPM 0.24 (7 -29) (2.26) (1.93) 436 WNMK = 3.71 - 0.85 [-0.241 WVFP - 0.31 [-0.121 DIST 0.08 (5.24) (2.53) 374 HfiMK = 2.93 + 0.13 [0.30] HYRS - 0.71[-0.241 HVFP + 0.04 [O.l2]HKPM 0.24 (5.54) (5.13) (2.20) 415 WA CW = 4.89 - 0.91 [-0.571 NSC - 0.12 [-0.091 WMOD (14.31) (2.25) 372 HACW = 4.07 - 0.93 [-0.781 NSC - 0.08 [-0.081 HMOD (23.97) (2.59) 422 BFLC = -7.73 + 19.06 [0.45] SLC + 0.44 [0.15] WAGE ( 10.20) (3.54) 342 LLO = 74.25 + 0.99 [0.51] .FLC + 0.11 [1.12] WAGESQ 0.32 -5.60[-0.961 WAGE (2.81) l i n e a r fashion. A t e a r l i e r a g e s b i r t h i n t e r v a l decrease with age, but t h i s p a t t e r n i s reversed a t o l d e r ages. Controlling f o r age, t h e only s i g n i f i c a n t v a r i a b l e i s l e n g t h of b r e a s t f e e d i n g . An a d d i t i o n a l month of b r e a s t f e e d i n g a d d s about one month t o t h e i n t e r v a l . T h i s i s much h i g h e r t h a n e s t i m a t e s of the. e f f e c t of b r e a t f e e d i n g on araenohrrea and may b e i n p a r t s p u r i o u s . If r e s t r i c t o u r sample t o t h o s e who a r e n o t now being b r e a s t f e d , t h i s s p u r i o u s element i s removed and t h e c o e f f i c i e n t f o r b r e a s t f e e d i n g i n d i c a t e s t h a t a n a d d i t i o n a l month of b r e a s t f e e d i n g adds 17 d a y s t o t h e l e n g t h of t h e i n t e r v a l . Of t h e s e d e t e r m i n a n t s of t h e l a s t b i r t h i n t e r v a l , b r e a s t f e e d i n g i s s i g n i f i c a n t l y r e l a t e d p o s i t i v e l y t o t h e w i f e ' s a g e and s u r v i v a l of t h e l a s t child. The s u r v i v a l of a c h i l d a d d s over a year t o t h e l e n g t h of breastfeeding. I f e r e s t r i c t our sample t o t h o s e who have t e r m i n a t e d b r e a s t f e e d i n g we f i n d , s u r v i v a l a d d s 29 months t o b r e a s t f e e d i n g . 'Ihe number of a d d i t i o n a l c h i l d r e n a husband o r w i f e wants i s s i g - n i f i c a n t l y r e l a t e d t o t h e i r r e s p e c t i v e m o d e r n i t y and t h e number of s u r v i v i n g c h i l d r e n t h e y have. Both m o d e r n i t y and l a r g e number of s u r v i v i n g c h i l d r e n reduce t h e d e s i r e f o r a d d i t i o n a l c h i l d r e n . i-fodernity f o r husband and w i f e depends on y e a r s of schooling a n d ' i n t e l l e c t u a l ability. I n a d d i t i o n , a man's modernity d e p e n d s on h i s f a t h e r ' s l i t e r a c y and a woman's m o d e r n i t y depends on h e r husband's l i t e r a c y . - U n f o r t u n a t e l y , f a m i l y s i z e d e s i r e s and t h e d e i r e f o r r - L . a d d i t i o n a l c h i l g r e n do n o t a f f e c t behavior. E !e I 1 - - / T h i s d a t a s e t shows v e r y long p e r i o d s of b r e a s t f e e d i n g . We feel this a c c u r a t e l y r e f l e c t s behavior. It i s a l s o c o n s i s t e n t w i t h a t t i t u d e s on how long people f e e l a c h i l d should be b r e a s t f e d . For women t h e mean v a l u e i s s l i g h t l y under 4 y e a r s and t h e modal v a l u e i s 5 years. For men t h e s e d i a n i s s l i g h t l y under 5 y e a r s and t h e mode i s 3 y r s . These a r e v e r y long p e r i o d s n o t u n l i k e A£rica where long breastfeteding i s considered necessary f o r child survival.  Another d i s a p p o i n t i n g r e s u l t from a p o l i c y p e r s p e c t i v e i s t h a t with r e s p e c t t o t h e husband's and w i f e ' s knowledge of c o n t r a c e p t i o n . The number of methods known f o r b o t h hvlsband and w i f e depends on whether o r n o t t h e y have been v i s i t e d by a f a m i l y planning worker a s w l l a s on d i s t r i c t f o r wives and on i n t e l l e c t u a l a b i l i t y and schooling f o r husbands. I n e a r l i e r r e s u l t s we found t h a t number of methods known m a r g i n a l l y a f f e c t e d t h e number of addlition- a 1 c h i l d r e n wanted. l k i s had c l e a r p o l i c y i m p l i c a t i o n s but t h e f i n d i n g was not robust. The nunber of a d d i t i o n a l c h i l d r e n one h a s i s more c l e a r l y r e l a t e d t o t h e number of s u r v i v i n g c h i l d r e n t h a n t o modernity, however. The r e l a t i v e importance of modernity i s between 10 and 22 p e r c e n t of t h a t of surviving children. l h i s a n a l y s i s i n d i c a t e s t h a t while t h e demand f o r c h i l d r e n and c o n t r a c e p t i v e knowledge c a n be i n f l u e n c e d i n p r e d i c t a b l e ways, t h e binding c o n s t r a i n t on f e r t i l i t y i s b i o l o g i c a l . Couples want more c h i l d r e n t h a n t h e y can have g i v e n high m o r t a l i t y and poor h e a l t h a s evidenced by long f i r s t birth intervals. Therefore i n t h e next s e c t i o n w e s h a l l c a r e f u l l y examine t h e d e t e r m i n a n t s of c h i l d s u r v i v a l . SURVIVAL OF OFFSPRIXG Analyzing c h i l d s u r v i v a l i s more d i f f i c u l t than a n a l y z i n g c h i l d r e n e v e r born because of problems of sample s i z e - / and e q u a t i o n s 3 e c i f i c a t i o n . 2 Given t h e s e problems our a n a l y s i s below i s o n l y s u g g e s t i v e , b u t t h e r e a r e s e v e r a l p o i n t s w e wish t o examine. - 1/ - There a r e many fewer d e a t h s t h a n b i r t h i n t h e sample and t h e r e f o r e S e s t i m a t i n g t h e p r o p o r t i o n surviving i s - s u b j e c t t o g r e a t e r e r r o r and needs a l a r g e r sample f o r accuracy. - 2/ The dependent v a r i a b l e whether i t be t h e p r o p o r t i o n of c h i l d r e n s u r v i v i n g o r t h e s u r v i v a l of l a s t c h i l d i s n o t a normally d i s t r i b u t e d v a r i a b l e and t h e r e f o r e o r d i n a r y l e a s t s q u a r e s i s n o t s t r i c t 1y speaking a p p r o p r i a t e , but w e s h a l l u s e i t a s a f i r s t approximation.  Table 5a: SURVIVAL OF OFFSPRING AS A FUNCTION OF EXPOSURE AND SOCIO-ECONOMIC VARIABLES Pro~ortionof C h i l d r e n S u r v i v i n g f o r 502 Women PCS = .833 - .026 1-.193] CEB + -063 [.098] HLIT i2 = .05 (4.42) (2.23) PCS = .801 - .005:.153] Exp + .060 [ .093] HLIT E2 = .03 (3.45) (2.10) PCS = .838 - .022 [.165] CEB -.001 [.043] EXP (2.82) (0.74) + .061 [.095] HLIT ' (2.16) PCS = .868 - .022 [.I621 CEB - .001 1.0481 EXP (2.77) (0.82) + 0.56 [.086] HLIT + .002 [.025] CATTLE (1.92) (0.55) - .024 [.042] DISTRICT (0.94) PCS = 0.839 - 0.005 [0.155] EXPO + 0.053 [0.084] HLIT (3.50) (1.87) - 0.002 [0.021] CATTLE - 0.028 (0.0491 DISTBICT R~ = .03 (0.48) (1.11) e f f e c t , b u t s i n c e i t i s h i g h l y c o r r e l a t e d w i t h t h e number of c h i l d r e n e v e r born i t w a s - s i g n i f i c a n t o n l y i f t h e l a t t e r was d e l e t e d . The most d i f f i c u l t v a r i a b l e t o d e a l w i t h i s t h e one t h a t i s most significant - children ever born. This can be used a s a measure of crowding of resources - p a r t i c u l a r l y m a t e r n a l d e p l e t i o n , b u t i t i s a l s o h i g h l y probable t h a t c h i l d r e n e v e r born and t h e p r o p o r t i o n s u r v i v i n g a r e s i m u l t a n e o u s l y determined. T h i s p o i n t w i l l be d i s c u s s e d i n d e t a i l below. S u r v i v a l of t h e Most Recent B i r t h The s u r v i v a l of a b i r t h depends l o g i c a l l y t o a l a r g e e x t e n t on t h e exposure t o d e a t h o r t h e time s i n c e t h e b i r t h of t h e c h i l d . The sex of t h e c h i l d is a l s o important i n determining c h i l d s u r v i v a l i n some circumstances. Other v a r i a b l e s which may b e important a r e c h i l d r e n e v e r born t o t h e muther through i t s e f f e c t on m a t e r n a l d e p l e t i o n and p r e s s u r e on household r e s o u r c e s , t h e l e v e l of household economic r e s o u r c e s , p a r e n t a l i n t e l l e c t u a l a b i l i t i e s and t h e p r o p o r t i o n of a l l p r e v i o u s c h i l d r e n who have s u r v i v e d . Preliminary a n a l y s i s of household landownership, household b u i l d i n g m a t e r i a l s and a g r i c u l k u r a l production showed no r e l a t i o n s h i p t o t h e s u r w i v ~ l of t h e l a s t c h i l d . In addition, neither parental intellectual characte~cistics nor h e a l t h knowledge was s i g n i f i c a n t l y r e l a t e d t o s u r v i v a c of t h e most recent '9 - - L birth. The o n l y socioeconomic v a r i a b l e t h a t showed any s i g n i f i c a n c e was t h e - n u a e r of c a t t l e owned. - C a t t l e ownership was p o s i t i v e l y d l a t e d t o t h e s u r v i v a l of t h e l a s t c h i l d i n t h o s e c a s e s where t h e s u r v i v a l of p r e v i o u s c h i l d r e n was n o t included i n t h e a n a l y s i s . ey.posure which was r e l a t e d i n a non-linear - f a s h i o n t o s u r v i v a l 11 and t h e s u r v i v a l of p r e v i o u s c h i l d r e n . Table 5b shows t h a t exposure v a r i a b l e s were t h e most i m p o r t a n t followed by t h e s u r v i v a l of p r e v i o u s c h i l d r e n . The s e x of t h e c h i l d was t h e c e x t most important v a r i a b l e b u t was not c o n s i s t e n t l y significant. - 1 2 C a t t l e o v n e r s h i p was s i m i l a r i n importance t o t h e s e x of t h e c h i l d and was o c c a s i o n a l l y s i g n i f i c a n t i n t h e expected d i r e c t i o n . The number of c h i l d r e n e v e r born was s i m i l a r t o c a t t l e and s e x ir. i t s r e l a t i v e importance, b u t was r a r e l y s i g n i f i c a n t . The f a c t t h a t c h i l d r e n e v e r born has l i t t l e e f f e c t ( i n f a c t none i f t h e s u r v i v a l r a t e f o r e a r l i e r b i r t h s i s c o n s i d e r o d ) o n t h e s u r v i v a l of t h e l a s t c h i l d seems t o imply t h a t t h e r e l a t i o n s h i p between s u r v i v a l of a l l c h i l d r e n and c h i l d r e n e v e r born found above i s n o t t h e r e s u l t of crowding o r d e p l e t i o n b u t probably t h e e f f e c t of c l o s e r c h i l d s p a c i n g r e s u l t i n g from t e r m i n a t i o n of b r e a s t f e e d i n g and t h e r e t u r n of o v u l a t i o n . 31 - O v e r a l l t h e s e d a t a i n d i c a t e t h a t w e c a n p r e d i c t s u r v i v a l of t h e l a s t c h i l d b e t t e r t h a n t h e p r o p o r t i o n of c h i l d r e n s u r v i v i r , g . Unfortcnately, most of t h e p r e d i c t i v e power i n b o t h models r e s u l t from b i o l o g i c a l r e l a t i o n - sKips such a s exposure and t h e s u r v i v a l of p r e v i o u s ~ c h i l d r e n . Husband's - 11 The l e n g t h of t h e open i n t e r v a l , LLO, i s t h e p e r i o d of exposure. This shows t h a t e x p o s u r e ' s n e g a t i v e e f f e c t on s u r v i v a l is c o n c e n t r a t e d i n - t h e e a r l y p e r i o d of exposure a s might be e x p e c t e d . - 21 Female c h i l d r e n show h i g h e r a o r t a l i t y I . - 3/ Another t e s t of t h e crowding o r m a t e r n a l d e p l e t i o n e f f e c t was made by e s t i m a t i n g t h e e f f e c t of t h e time between b i r t h s and the s u r v i v a l of t h e second b i r t h . The time between t h e n e x t t o l a s t c h i l d and t h e l a s t c h i l d was n o t s i g n i f i c a n t l y r e l a t e d t o s u r v i v a l of t h e l a s t c h i l d .  - l i t e r a c y i s t h e most i m p o r t a n t socioeconomic v a r i a b l e , l/ but w e a l t h a s measured by c a t t l e ownership i s o c c a s i o n a l l y s i g n i f i c a n t f o r s u r v i v a l of t h e most r e c e n t b i r t h . U n f o r t u n a t e l y , o u r d a t a d i d not i n c l u d e p o l i c y v a r i a b l e s s u c h a s d i s t a n c e t o c l i n e s , b u t did i n c l u d e a dummy v a r i a b l e f o r d i s t r i c t and t h i s was n o t s i g n i f i c a n t . EVIDENCE OF THE CAUSAL RELATIONSHIP BETWEEN CHILD SURVIVAL IWD FERTILITY To t h i s p o i n t we have n o t d i s c u s s e d i n d e t a i l t h e c a u s a l r e l a t i o n - s h i p between c h i l d s u r v i v a l and t h e number of c h i l d r e n e v e r born. There a r e a t ' l e a s t f o u r d i f f e r e n t hypotheses about how t h e s e a r e r e l a k e d . The hypo- t h e s e s d i f f e r i n t h e d i r e c t i o n of c a u s a t i o n assumed and i n t h e mechanism, b i o l o g i c a l o r i l o h a v i o r a l , through which t h e r e l a t i o n s h i p i s brought about. Mechanism Directj-on of C a u s a t i o n Biological Behavioral itlortality Affects F e r t i l i t y I II F e r t i l i t y P f f e c t s Mortality I1I IV I. I f a c h i l d d i e s , l a c t a t i o n w i l l , be t e r m i n a t e d p r e m a t u r e l y ; o v u l a t i o n w i l l r e t u r n more q u i c k l y and b i r t h i n t e r v a l s w i l l be s h o r t e n e d and more b i r t h s w i l l occur i n t h e c o u r s e g f m a r r i a g e . .a 1/ - L Husband's l i t e r a c y 3 f e c t s t h e s u r v i v a l of a l l c h i l d r e n d i r e c t l y . It a l s o -. a f f e c t s t h e s u r v i v a l - o f t h e most r e c e n t b i r t h i n d i r e c t l y through i t s e f f e c t on t h e s u r v i v a l of p r e v i o u s c h i l d r e n . For t h e 455 c a s e s where d a t a a r e a v a i l a b l e , t h e o n l y v a r i a b l e which h a s a s i g n i f i c a n t e f f e c t on t h e s u r v i v a l of p r e v i o u s c h i l d r e n is husband's l ~ t e r a c y . SPS = .64 + .078 [ 0 . 0 9 6 ] HLIT. (2.06) Thus t h e i n d i r e c t . e f f e c t of husband's l i t e r a c y on t h e s u r v i v a l of t h e l a s t c h i l d would b e a p p r o x i m a t e l y .02. That i s , a l i t e r a t e husband's c h i l d woul2 have a 2 p e r c e n t lower m o r t a l i t y o v e r t h e a v e r a g e exposure p e r i o d of 4 1 / 2 y e a r s f o r a l l c h i l d r e n .  11. (a) I f a ci.ild d i e s , p a r e n t s w i l l want t o r e p l a c e t h a t c h i l d and f e r t i l i t y w i l l be h i g h e r . (b) A l t e r n a t i v e l y , t h e h i g h e r t h e o v e r a l l l e v e l s of m o r t a l i t y , t h e h i g h e r f e r t i l i t y w i l l be i n a n t i c i p a t i o n of c h i l d m o r t a l i t y . 111. The more c h i l d r e n i n a f a m i l y , t h e f e w e r t h e r e s o u r c e s p e r c a p i t a and i n p a r t i c u l a r t h e p o o r e r t h e h e a l t h of t h e m c t h e r and t h e h i g h e r t h e chances a c h i l d w i l l d i e . IV. The g r e a t e r t h e f e r t i l i t y i n t h e f a m i l y , t h e fewer a d d i t i o n a l c h i l d r e n a r e wanted and a s a consequence t h e r e may b e more n e g l e c t of chtl.dren and h i g h e r m o r t a l i t y might be a n i m p l i c i t form of f e r t i l i t y c o n t r o l . A l l of t h e s e h y p o t h e s e s g e n e r a t e a n e g a t i v e r e l a t i o n s h i p between t h e p r o p ~ r t i o nof c h i l d r e n s u r v i v i n g and t h e number of c h i l d r e n e v e r born. T h i s n e g a t i v e r e l a t i o n s h i p is confirmed i n t h e e v i d e n c e , b u t c o r r e l a t i o n s o r r e g r e s s i o n s between c h i l d r e n e v e r born and s u r v i v a l c a n n o t y i e l d i n s i g h t i n t o the causality. I f one s p e c i f i e s t h e mechanisms through which t h e two v a r i a b l e s may a f f e c t e a c h o t h e r , t h e r e is some hope of s o r t i n g o u t c a u s a t i o n . I n t h e d i s c u s s i o n below we s h a l l c o n c e n t r a t e on t r y i n g t o d e t e r m i n e t h e d i r e c t i o n of c a u s a t i o n , b u t w i l l n o t t r y t o make any s t r o n g s t a t e m e n t s about whether t h e r e l a t i o n s h i p i s brought a b o u t by b e h a v i o r a l o r b i o l o g i c a l factors._l/ 3 I Thus we s h a l l e x p l z r e two t y p e s of r e l a t i o n s h i p s : t h o s e i n which c h i l d s u r v i v a l may a f f e c t f e r t i l i t y and t h o s e i n which f e r t i l i t y might a f f e c t - i survival. .% L - - e s h a l l o n l y be a b l e t o s o r t o u t c a u s a t i o n if w e c a n u s e v a r i a b l e s W & i c h have c l e a r o r d e r i n g i n t i m e o r f o r which t h e o r y 8 sufficiently strong 1/ - U n f o r t u n a t e l y , o u r d a t a on whether a c h i l d may o r may n o t have been wanted a r e e x p o s t e . T h e r e f o r e i n a measurement s e n s e , f e r t i l i t y o r m o r t a l i t y can o n l y a f f e c t wantedness and n o t t h e c o n v e r s e . Simmons and B e r n s t e i n have used s u c h ex p o s t measures of wantedness t o e x p l a i n s u r v i v a l (1981). Our r e s u l t s a r e so u n s t a b l e , however, t h a t we have l i t t l e c o n f i d e n c e i n them f o r e x p l a i n i n g whether r e l a t i o n s h i p s a r e t h e r e s u l t of b e h a v i o r a l f a c t o r s . t h a t we c a n e l i m i n a t e c e r t a i n c a u s a l d i r e c t i o n s . One t e s t of t h e e f f e c t of f e r t i l i t y on s u r v i v a l i s t o examine t h e r e l a t i o n s h i p between c h i l d r e n e v e r born and t h e s u r v i v a l of t h e most r e c e n t b i r t h . The l a t t e r cannot a f f e c t the former. T h e r e f o r e , i f a r e l a t i o n s h i p e x i s t s , i t must mean t h a t f e r t i l i t y affects mortality. A second t e s t i s t o examine t h e e f f e c t of crowding through t h e - spacing of b..rths on c h i l d s u r v i v a l . I f crowding brought on by high f e r t i l i t y i s i m p o r t a n t , t h e n t h e s h o r t e r t h e i n t e r v a l between t h e l a s t two b i r t h s , t h e l e s s l i k e l y t h e l a s t b i r t h w i l l survive. I£ t h e s e two measures of high f e r t i l i t y do not a f f e c t t h e s u r v i v a l of t h e l a s t c h i l d , t h e n t h e r e i s a c a s e f o r a s s e y t i n g t h a t t h e c o r r e l a t i o n between c h i l d r e n e v e r born and s u r v i v a l r e s u l t s not from f e r t i l i t y ' s e f f e c t on s u r v i v a l , b u t from s u r v i v a l ' s e f f e c t on f e r t i l i t y . The e q u a t i o n s i n Table 5b show t h a t when t h e s u r v i v a l r a t e f o r previous b i r t h s i s i n c l u d e d i n t h e a n a l y s i s , c h i l d r e n e v e r born i s not significant. I f t h e s u r v i v a l of previous b i r t h s i s n o t i n c l u d e d c h i l d r e n e v e r born i s m a r g i n a l l y s i g n i f i c a n t a t t = -1.95. The z e r o o r d e r c o r r e l a t i o n i s a l s o low r e l a t i v e t o t h a t f o r p r o p o r t i o n s u r v i v i n g (-.098) versus ( - . 2 8 4 ) . a This s u g g e s t s t h a t t h e s u r v i v a l of previous c h i l d ' s main e f f e c t i s not t h e r e s u l t of crowding on t h e s u r v i v a l of p r e v i o u s b i r t h s . g - i Other e v i d e n c e confirms t h e l a c k of a crowding e f f e c t . The c l o s e r .? - L t o g e t h e r b i r t h s a r e , t h e h i g h e r t h e p r o b a b i l i t y of m o r t a l i t y i f crowding from * high f e r t i l i t y l e a d s t o rn high-mortality. The evidence shows, however, t h a t t h e * . I  l e n g t h of time between t n e l a s t two b i r t h s i s n o t c o r r e l a t e d w i t h t h e siurvival of t h e youngest c h i l d . Thus n e i t h e r crowding n o r f e r t i l i t y a p p e a r t o be s i g n i f i c a n t i n t h e s e d a t a and f e r t i l i t y ' s e f f e c t on m o r t a l i t y is geak o r non-existent. The e v i d e n c e on t h e e f f e c t of s u r v i v a l on f e r t i l i t y i s somewhat s t r o n g e r but n o t unequivocal. As shown i n Table 4, c h i l d s u r v i v a l prolongs b r e a s t f e e d i n g and b r e a s t f e e d i n g prolongs t h e time s i n c e l a s t b i r t h , and t h i s b r a a s t f e e d i n g e f f e c t is second o n l y t o age i n d e t e r m i n i n g t h e l e n g t h -of the b i r t h i n t e r v a l . It c o u l d be t h a t s i l r v i v a l ' s e f f e c t on b r e a s t f e e l i n g i s only p a r t of t h e r e l a t i o n s h i p . B r e a s t f e e d i n g may a l s o a f f e c t s u r v i v a l . We find that i n 306 and 489 c a s e s t h e c h i l d i s e i t h e r c u r r e n t l y b r e a s t f e e d i n g o r was b r e a s t f e e d i n g a t t h e time i t d i e d . I n those cases breastfeeding termination could n o t have l e d t o m o r t a l i t y . I n t h e o t h e r 183 - 2/ c a s e s we f i n d t h a t b r e a s t f e e d i n g i s t h e moct i m p o r t a n t v a r i a b l e " e x p l a i n i n g " s u r v i v a l : SLC = .638 + 0.008 [0.48] BFLC + 0.23 [0.24] PCSLC - 0.002 [0.43] LLO (7.01) (3.69) (2.39) - 11 The e q u a t i o n is: SLC = 0.829 - 0.002 LLO + 0.000 LLO' + 0.259 SPC . -.048 SEX + .005 CATTLE + (4.69) .000 LC1 (2.85) E' - = .14, n = 489 (6.04) (1.67) (1.25) (1.16)  - 28 - Thus b r e a s t f e e d i n g and s u r v i v a l p r o b a b l y r e p r e s e n t a s i m u l t a n e o u s system i n t h i s subsample, 1; but f o r t h e m a j o r i t y of t h e sample ( t h o s e 263 c u r r e n t l y b r e a s t f e e d i n g and t h e 42 who d i e d w h i l e b e i n g b r e a s t f e d ) , t h e l e n g t h of b r e a s t f e e d i n g might a f f e c t t h e l e n g t h of t i m e t h e y s u r v i v e , b u t t e r m i n a t i o n < of b r e a s t f e e d i n g c o u l d n o t have been t h e c a u s e of d e a t h . Therefore, f o r the m a-j o r i t y , c a u s a t i o n c o u l d o n l y have been from s u r v i v a l t o b r e a s t f e e d i n g . SUMMARY AND CONCLUSION Our a n a l y s i s shows t h a t l i f e t i m e f e r t i l i t y i s p r i m a r i l y a function of e x p o s u r e t o c h i l d b e a r i n g and a b i l i t y t o c o n c e i v e a s measured by t h e f i r s t b i r t h interval (i.e. on biological variables). The a g e o f c o h a b i t a t i o n a f f e c t s f e r t i l i t y t h r o u g h e x p o s u r e and i t s e l f is a f f e c t e d by t h e w i f e ' s i n t e l l e c t u a l a b i l i t y o r t h e husband's f a t h e r ' s l a n d o w n e r s h i p depending on t h e sample. Both of t h e s e f a c t o r s r a i s e t h e a g e o f c o h a b i t a t i o n and t h u s r e d u c e f e r t i l i t y indirectly. r Husband's f a ~ k e ' s landownership i s a l s o d i r e c t l y r e l a t e d t o f e r t i l i t y i n a n e g a t i v e way f o r t h e s m a l l sample. This is contrary t o e x p e c t a t i o n s on t h e o r e t i c a l g r o u n d s , b u t many o t h e r s t u d i e s have found illcome o r a s s e t s n e g a t i v e l y ? e l a t e d t o f e r t i l i t y . - 14 T h i s p a r t i c u l a r s i m u l t a n e c u s system h a s be!en e s t.imat e d, by u s e s t a g e l g a s t squares. ( P r o b i t was u s e d t o p r e d i c. t t h e s u r v i v a l WO the - - l a s t child) * + 0.90 + I BFCC = -20.15 WAGE 32.66 SLC (6.27) (2.75) 1 SLC = 0.58 - .001 LLO + -000 LLOSQ - -081 SEX (1.52) (1.28) combination with the f a c t t h a t f e r t i l i t y i,?constrained by b i o l o g i c a l f a c t o r s L - s u g g e s t s t h a t u n l e s s c h i l d s u r v i v a l i s impwved, t h e r e w i l l be l i t t l e d.emand f o r contraceptives. A t the same time, * our d a t a i n d i c a t e t h a t the demand f o r  REFERENCES Bongaarts. J. 1978. "A Framework for halyzine. the Proximate Determina.nts of Fertility ." Population and Development Review, 4, pp. 105-132. Easterlin, R. A. et al.. 1980. "Toward a More General Economic Model of Fertility Determination: Endogenous Preferences and Natural Fertility." Population and Economic Change in Developing Countries, edited by R. A. Easterlin. Chicago: University of Chicago Press. Easterlin, R. A. and E. H. Crimmins. 1981. 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Meesook, " I n t e r r e l a t i o n s h i p s b e t w e n Demographic F a c t o r s and Income D i s t r i b u t i o n : Problems o f Measurement, D e s c r i p t i o n and Interpretation". A p r i l 1981. Susan H. Cochrane, Nirmala J o s h i and Kalpana Nandwani, " F e r t i l i t y A t t i t u d e s and B e h a v i o r i n t h e Nepal T e r a i " . A p r i l 1981. J.B. Knight and R i c h a r d S a b o t , "The R o l e o f t h e Firm i n L $e D e t e r m i n a t i o n : An A f r i c a n Case Study". A p r i l 1981. J.B. Knight and R i c h a r d S a b o t , "The R e t u r n s t o Education: Increasing with E x p e r i e n c e o r D e c r e a s i n g w i t h Expansion?". March 1981. J.B. Knight and R i c h a r d S a b o t , "From M i g r a n t s t o P r o l e t a r i a n s : . Employment E x p e r i e n c e , M o b i l i t y a n d %ggs i n Tanzania1'. Marclh 1981. A. B e r r y and R i c h a r d S a b o t , "Unemployment and Economic Develop~nent". A p r i l 1981. Rashid F a r u q e e and Ethna Johnson, "Health. N u t r i t i o n and Family P l a n n i n g : A Survey o f Experiments and S p e c i a l P r o j e c t s i n I n d i a " . A p r i l 1981. F r a n c o i s O r i v e l and Dean T. Jamlson, "The Cost-Ef f e c t i v e n e s s o f D i s t a n c e Teaching P r o j e c t s " . June 1981  - 2 - 81-16 Richard Sabot, "Labor Force Growth, Employment and Earnings i n Egypt: 1966-1968". May 1981. 81-17 K.C. Zachariah, "Anomaly o f t h e F e r t i l i t y D e c l i n e i n Kerala: Social 81-18 Richard Sabot, A. Berry, A. H a z l e m o d , J. Knight, P. C o l l i e r , J. Armitage, M. B o i s s i e r e , "Education Expansion and Labor M a r 1 e t Adjustment i n Kenya and Tanzania - A B a c k r o u n d Paper". May 1981. 81-19 Nancy B i r d s a l l and Oey Meesook, "Child Schooling, Number of C h i l d r e n and I n t e r g e n e r a t i o n a l T r a n s m i s s i o n of I n e q u a l i t y : A Simulation". May 1981. 81-20 F r a n c o i s O r i v e l , "The Impact of A g r i c u l t u r a l E x t e n s i o n S e r v i c e s : A Review o f t h e L i t e r a t u r e " . J u l y 1981. Also a v a i l a b l e i n French ~ittBrature" . 81-21 Nancy B i r d s a l l and M. Louise Fox, "Ghy Males Earn More: Location, Job P r e f e r e n c e s and J o b D i s c r i m i n a t i o n Among B r a z i l i a n Schoolteachers". May 1981. 81-22 A l t h e a H i l l , "The Demographic S i t u t a t i o n i n Sub-Saharan Africa:: A D i s c u s s i o n Paper". May 1981. 81-23" R. Sabot, A. B e r r y , A. Hazlemod, J. Knight, J. Armitage, M. B o i s s i e r e "Does t h e Expansion of Educetior. Compress t h e S t r u c t u r e of k g e s and Redule t h e I n e q u a l i t y of Pay? A P r e l i m i n a r y Analysis". J u l y 1981. 81-24* Nancy B i r d s a l l and Dean T. Jamison "Income and Other F a c t o r s Bnf l u e n c ing F e r t i l i t y and M o r t a l i t y i n China". Forthcoming . 81-25* Nancy B i r d s a l l , S u l e h a P a t e 1 and K . C. Zachariah, " A l t e r n a t i v e . P r o j e c t i o n s o f t h e Chinese Yopulation". I J u n e 1981. 81-26* T.J. Ho, Dean T. Jamison, and F.L. Trowbridge. "Food A v a i l a b i l i t y and t h e N c t r i t i o n a l S t a t u s of C h i l d r e n in China". Forthcoming. Forthcoming . E-28 Deborah Lhamon Macmillan. "Language P o l i c i e s f o r A f r i c a n Primary .:ducation: Summary o f t h e Anglophone Research L i t e r a t u r e . " J u l y 1981. - 81-29 T a n f a Thevenin. "Les I m p l i c a t i o n s Pedagogiques d e s P o l i t i q u e s d e l a n g u e s d a n s l'enseignement e n Afrlque: Une revue d e i a l i t t e r a t u r e Francophone". 1981. Also a v a i l a b l e In Eng l l s h a s "Pedagogical J ~ n e I m p l i c a t i o n s o f Language P o l i c y i n A f r i c a n Schools: A Review o f t h e Francophone L i t e r a t u r e " .  81-30 V i c e n t e Paqueo. "A Household P r o d u c t i o n Model o f School Enrollment: A P r o b i t A n a l y s i s o f t h e 1978 B i c o l M u l t i p u r p o s e Survey D ~ t a " . June 1981 81-32 Reynaldo M a r t o r e l l . " N u t r i t i o n and H e a l t h S t a t u s I n d i c a t o r s : S u g g e s t i o n s f o r Surveys o f t h e S t a n d a r d o f L i v i n g i n Developing Countries". J u n e 1981. 81-33* R. S a b o t , A. B e r r y , A. Hazelwood, J. Knight, J. h i t a g e , a n d > M. B o i s s i e r e . " C o r r e l a t e s o f E d u c a t i o n a l A t t a i n m e n t i n Tanzania". J u l y 1981. 81-34 Susan H. Cochrane. "The D e t e r m i n a n t s o f F e r t i l i t y and C h i l d S u r v i v a l i n t h e Nepal T e r a i " . J u l y 1981. 81-35 J o a n n e L e s l i e , B.G. Baidya, and K . Nandwani. "Prevalence and C o r r e l a t e s o f Childhood M a l n u t r i t i o n i n t h e T e r a i Region o f Nepal". J u l y 1981. 81-36 R. Mansell P r o t h e r o . " P e r s p e c t i v e s o n P o p u l a t i o n M o b i l i t y i n West Africa". August 1981. 81-37 Timothy King. " P o p u l a t i o n Growth, I n t e r n a t i o n a l Resource T r a n s f e r s , a n d I n t e r n a t i o n a l Migration". August 1 9 8 1 81-38 Timothy King. "Immigration from Developing C o u n t r i e s : Some Philosophical Issues". August 1981. 81-39 R. S a b o t a r d J . Knight. ' m y Wages D i f f e r : E a r n i n g s Funct-lons i n a Poor Urban Economy". August 1981. 81-40 J o a o B a t i s t a d e A r a u j o e O l i v e i r a s and F r a n c o i s O r i v e l . "In-Serv?ce Teacher T r a i n i n g System: Logos I1 i n ~ r d z i l " . August 1981. 81-41 R. S a b o t , A . B e r r y , A. Hazlewood, J. Knight, J. A m i t a g e and M. B o i s s i e r e . orre relates of E d u c a t i o n a l A t t a i n m e n t i n Kenya". August 1981. ,3 L 81-42 P e t e r F a l l o n . "Inccunes, P o v e r t y and Income D i s t r i b u t i o n i n R u r a l Botswana: A s y n t & s i s of Evidence Based on t h e R u r a l 1ncorr.e 81-43 B a r b a r a Watanabe and Eva M u e l l e r . "A P o v e r t y P r o f i l e f o r R u r a l Botswana." Forthcoming. 81-44 Eva M u e l l e r . "The Value and A l l o c a t i o n of Time i n R u r a l Botswana." Forthcorninn.