EARLY-CHILDHOOD NUTRITION, SCHOOLING, AND SIBLING INEQUALITY 79


Table 4.5 Age at which school was started Explanatory variable


(1) Height-for-age z-score, 1998 Female


Current age fixed effects Cluster fixed effects Household fixed effects


Sargan overidentification (p-value) Mean age started


Mean height-for-age z-score Within-cluster R2


Within-household R2 Number of children Number of groups


6.0155 6.1717 0.4541


322 55


99 46


(2)


(3)


(4)


–0.0827 –0.1367 –0.4790 –0.1477 (2.87) (1.78) (1.98) (1.10)


–0.0474 –0.1766 –0.2957 –0.1805 (0.47) (0.98) (1.28) (0.98)


Yes Yes


Yes Yes Yes Yes 13.052


(0.0015) 6.1717


0.2138


99 46


Yes Yes n.a. 6.1717


–0.7164 –0.6892 –0.6892 –0.6892 0.1763


0.4539


99 46


Sources: South African Labour and Development Research Unit, University of Cape Town (1994); University of KwaZulu-Natal / International Food Policy Research Institute / University of Wisconsin–Madison (1998, 2004).


Notes: Dependent variable is age at which school was started. Numbers in parentheses are absolute t-values. Estimation with household (cluster) fixed effects uses children from households (clusters) with multiple children. Specifications include age fixed effects, and over-age and under-age indicators for reported age in 1998. Sample consists of children aged 1–4 years in 1998 and 7 years or above in 2004, with consistent ages between 1998 and 2004, height-for-age z-score in the range –6 to 6 in 1998, and age at which school was started equal to 4 years or above. In column 4, the equation is just identified. n.a. means not available.


and aged 7 or above in 2004.16 Column 1 controls only cluster-level fixed effects, while Columns 2 and 3 report within-sibling estimates. The specifica- tions include current age indicators to control cohort effects. In column 1, greater child height is found to significantly lower the age at which the child started school, though this estimate is likely to be biased owing to a correla- tion between household-level factors and child height.


16 Since older children are more likely to be already in school than younger children, this type of sample selection affects estimated height effects on age schooling started. If the height effect is positive, those who are relatively well endowed are likely to be dropped from the sample, especially among older children (ages 4 and 5). As a result, the selection biases the estimate upward (smaller in absolute value).


The enrollment rates among children age 7 or above are quite high in this sample (KIDS round 3, Section 12.2): 99.04 percent (age 7), 100 percent (age 8), 99.51 percent (age 9), 99.51 per- cent (age 10), and 98.73 percent (age 11). Therefore, omitting children who had not started schooling is not consequential.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150