of age.<sup>17</sup> Weight for age measures underweight and is the most commonly used measure of child nutritional status. It is routinely collected in growth promotion programs and is a particularly good indicator for children under two because of the need to do precise measurements of weight for this age group. Height for age is a measure of possible stunting or chronic malnourishment. It is generally assumed to indicate the long-term, cumulative effects of inadequate nutrition and poor health status. It is thus the measure which has the greatest relevance from our perspective, since we use cross section data and are interested in observing the impact of a nutritional shock at any time in the child’s fi rst 3 years of life. For height for age, therefore, we divide children into two groups: 6 months to 3 years and 3-10 years of age. A child is considered malnutrient if either of these indexes falls below two standard deviations (<-2SD) of the median value of the National Center for Health Statistics/World Health Organization (NCHS/WHO) international reference. Severe malnutrition is identi fi ed by index values below 3 SD of the median value.<sup>18</sup> The fi nal sample of children is con fi ned to those with z-scores in the range -6 to 6.<sup>19</sup> This gives us a total sample of 4731 children for whom we have HAZ scores in the acceptable range (of which 1157 are under age 3) and 4906 children with WAZ scores in this range. About 27% of these children belong to migrant households. The mean HAZ is -1.92. More than half the sample (54%) has HAZ scores which are below -2 SD a level that signi fi es some stunting and about a third have score below -3 indicating severe stunting.<sup>20</sup> The mean WAZ in this sample is -1.82. Close to 44% of the sample has WAZ scores below -2 SD and 23% have scores below -3 indicating severe malnourishment. In contrast, 29% have HAZ scores in the normal range and 31% have WAZ scores in the normal range.

and sex the child’s height is one standard deviation below the median child in that age/sex group. Child height and weight in the PRHS 2001-02 were measured in centimetres and kilograms, respectively. The reference tables for WAZ and HAZ are taken from the CDC Growth Charts for US (Kuczmarski et al., 2000).

> 17 The use of z-scores is not recommended for children older than age 10.

> 18 We do not focus on weight for height (a measure of wasting). Like weight for age, it is sensitive to changes in calorie intake or the effects of disease, but is the best index to use to re fl ect wasting malnutrition, when it is difficult to determine the exact ages of the children being measured. In the population we study, we measure age well. Acute malnutrition is not as pervasive as malnutrition or stunting. The 1990 DHS estimates that 8.7% of children nationally are wasted.

> 19 Scores outside this range are typically indicative of measurement error in either height, weight or age. In doing this we follow the convention used for dealing with extreme z-score values. See for example, Hoddinott and Kinsey (2001).

X children with z-scores outside this range were dropped from the sample. These children do not appear to be a selective group by location, age or gender.

> 20 This is somewhat higher than the 48.9% stunting rate reported for the country as a whole in the Demographic and Health Survey (1990) This is not surprising given that the PRHS sample includes only rural children.

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