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Income Diversification and Poverty Income Diversification and Poverty

Income Diversification and Poverty Income Diversification and Poverty

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Chapter 3. Patterns <strong>and</strong> trends in diversification<br />

3.9 Determinants of income diversification<br />

This section examines the effect of different household characteristics on patterns of income<br />

diversification among rural households in Vietnam using data from the 1998 Vietnam Living<br />

St<strong>and</strong>ards Survey. The hypothesis is that the share of income from different sources is influenced by<br />

the characteristics of the household, particularly the amount <strong>and</strong> quality of labor, the amount <strong>and</strong><br />

quality of l<strong>and</strong>, access to markets, access to electricity, <strong>and</strong> the region. We use a linear model in<br />

which the income share is a function of household characteristics 24 . The characteristics included in<br />

the analysis are 25 :<br />

• age of the head of household (years),<br />

• age squared of the head,<br />

• education of the head of household (years),<br />

• household head is a member of ethnic minority (=0 if Kinh or Hoa, =1 otherwise),<br />

• household size (members),<br />

• proportion of household members under 10 (fraction),<br />

• proportion of household members over 60 (fraction),<br />

• female-headed household (=1 if female-headed),<br />

• household has electricity in the home,<br />

• annual crop l<strong>and</strong> (m2),<br />

• perennial crop l<strong>and</strong> (m2),<br />

• irrigated crop l<strong>and</strong> (m2),<br />

• distance from village to a paved road (km),<br />

• number of months per year road to village is impassible, <strong>and</strong><br />

• dummy variables for region (Red River Delta is reference region).<br />

Access to credit, defined as the ability to obtain a loan, would be a useful variable to include,<br />

but the VLSS can only tell us whether or not a household has actually received credit. This variable is<br />

less useful in the regression analysis because it is endogenous. A farmer may seek a loan because he<br />

wants to diversify, so that the coefficient would be affected by simultaneity bias.<br />

The first model estimates the share of income from crop production (see Table 3-35). Crop<br />

production is represents a smaller share of net income when the head of household has more<br />

education, presumably because education opens up opportunities for wage <strong>and</strong> enterprise income.<br />

Crop income is also a smaller share of the total when the head is female, probably due to the more<br />

limited availability of family labor <strong>and</strong> the greater likelihood of remittance income (as discussed<br />

below). Not surprisingly, the crop income share is also positively associated with the amount of<br />

24<br />

Because income shares are “clumped” at zero <strong>and</strong> (to a lesser degree) one, the assumption of a<br />

normally distributed error term is violated in this situation. The usual method of dealing with this situation<br />

would be to use a censored regression model (similar to a Tobit) with censoring below 0 <strong>and</strong> above 1.<br />

Unfortunately, the presence of negative values for net income (particularly for livestock income <strong>and</strong> enterprise<br />

income) means that the income share may be less than zero or greater than one, so that the assumptions of the<br />

Tobit model are also violated. Both linear <strong>and</strong> Tobit models were estimated <strong>and</strong> the results are broadly<br />

consistent, so we present on the results of the linear model.<br />

25<br />

Some variables were not used in the analysis because they might be endogenous (influenced by the<br />

occupation decision). For example, “credit” was not included because the choice of occupation could influence<br />

the decision whether to apply for credit. The VLSS did not collect information on the availability of credit.<br />

Page 79

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