household’s well-being such as the asset index should thus be considered.<sup>9</sup> Sahn and Stifel (2003) proposed to consider three categories of assets: household durables, housing quality and human capital.<sup>10</sup> The absence of comparable data sources on income and expenditures over the last decade motivates our use of the Demographic and Health Surveys (DHS)<sup>11</sup> as an alternative instrument for assessing changes in poverty and vulnerability, relying on an asset index as an alternative metric of welfare. The DHS are provided at three periods in Haiti: 1995, 2000 and 2005. It is then possible to compare the assets over the three surveys.

Among household assets, we first consider liquid assets since these assets can be sold to purchase basic commodities in the event of a drop in income. Second, we consider more durable assets such as housing and education, which can also be accumulated in order to protect households against poverty. Other intangible assets such as household relations and social capital may have been taken into account in the analysis, but they are not available in the data.

The asset index is a composite indicator that is a linear combination of categorical variables obtained from a multiple correspondence analysis:<sup>12</sup> where<sup>_a_</sup> _i_<sup>is the value of the asset index for the</sup><sup>_i_th observation,</sup> _dki_ is the value of the _k_ th dummy variable (with k=1,...,K) describing the asset variables considered in the analysis (liquid assets as well as housing variables and education of the head of the household), and _F_ 1 _k_ is the value of the standardized factorial score coefficient (or asset index weights) of the first component of the analysis.<sup>13</sup> Built this way, the asset index can be described as the

> 9 See, for instance, Sahn and Stifel (2000), Filmer and Pritchett (2001), Sahn and Stifel (2003), Booysen et al. (2008).

> 10 This list of assets is not exhaustive and could be completed following Moser (1998)’s asset-based approach. In her asset vulnerability framework, Moser (1998) identifies several categories of assets and illustrates how portfolio management affects vulnerability. Asset management includes: labor (e.g., the number of earners in the family and their income level), human capital (education and health), productive assets (such as housing in urban areas or cattle in rural areas), household relations and social capital.

> 11 The DHS surveyed households in Haiti’s nine departments. These departments were divided into 9 urban and 9 rural strata plus the metropolitan area of Port-au-Prince, amounting to a total of 19 strata. A two-stage sampling procedure was employed to select a representative sample of the target population. In the first stage, systematic sampling with probability proportional to the size of the strata was used to select 317 communities as clusters or primary sampling units (PSUs). In the second stage of sampling, households in each of the PSUs were systematically sampled.

> 12 See Benzécri (1973) or, more recently, Asselin (2009).

13 Alternatively, Sahn and Stifel (2000) used factor analysis, and Filmer and Pritchett (2001) used principal component analysis to measure their asset index. In reference to these methodologies, multiple correspondence analysis can be viewed as a principal component analysis applied to a contingency table with the chi2-metric being used on the row/column profiles, instead of the usual Euclidean metric. Multiple correspondence analysis provides information similar in nature to those produced by factor analysis and is less restrictive than principal component analysis.

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