# _Factors Affecting the Credibility of the 1993-1995 Results_

There are a number of problems associated with the 1993 and 1995 survey data, including sampling problems in 1993, the small sample size in 1995, the estimation of housing expenditure, the limited time period of the year during which the survey was conducted, the problem in correctly coding the consumption of home production data in 1993, the method used to estimate purchased food expenditure, and the non-representativeness of the consumer price index. In many cases the biases appear to be in the direction of overestimating the incidence of poverty in 1995.

## Survey design **and implementation**

A major difference between the 1993 and 1995 priority surveys is the size of the sample. The 1993 survey is based on a sample of 9,600 households, while the 1995 sample of 1,000 households is a little more than a tenth the size. The size of the some of the cells is very small in 1995, thus restricting the analysis one can do. Second, the 1993 sampling procedure was based on a household listing done in 1991. Surveying of the households began in March 1992, almost exclusively in Abidjan, but it was interrupted a few months later due to lack of money. Surveying resumed in June 1993 and was completed in November 1993. On average 22 months passed between the household listing and survey. A problem arose that many of the households that were listed in 1991 were not relocated in 1993. In urban areas, about 50 percent of the households selected were not surveyed, mostly because they could not be located, while in rural areas about a third of the households were not surveyed. Thus, the more stable households are over-represented in the sample, while the least stable-- and perhaps the poorest-are underrepresented. However, because of the high replacement rate in Abidjan, INS decided to keep the 1680 households in Abidjan that had been surveyed in 1992 as part of the sample, and to reject those that had been surveyed in 1993. Presumably, therefore, the Abidjan sample suffers less from this bias.

Another worrisome finding is the relatively large number of households in the 1993 survey that reported zero value for the sum of purchased expenditure and imputed value of consumption of home production (Appendix C). About one percent of households fall in this category. Some of these households did report receiving transfers of food from people outside the household, but is unlikely that transfers from outside the household would be the sole source of food. The relatively large number of households with zero food expenditure suggests that there may been problems with implementation of the survey or with data entry.

## **Decline in household size**

A troubling finding is the decline in household size between 1993 and 1995 (table 19). This would tend to raise per capita expenditure, all other things being equal, assuming that per capita household expenditure and household size are inversely correlated as is usually the case. Mean household size fell from 5.9 persons in 1993 to 5.5 persons in 1995, with the fall particularly acute in the West Forest. For Cote d'Ivoire as the whole, the 1993 estimate is not too dissimilar to the 1988 estimate of 6.2 persons. For export crop farmers, the 1988 estimate was 6.8, compared to the 1993 estimate of 6.7 and the 1995 estimate of 5.9 persons (table 20). The fall in household size is particularly large among export crop farmers who grow cocoa: household size declined from 7.1 to 5.9 persons between 1993 and 1995 (table 21). In contrast, food crop farmer household size did not decrease: mean household size rose slightly from 5.5 to 5.7 persons. Both estimates are somewhat lower than the 1988 estimate of 6.4 persons. Unfortunately without another source of information it is impossible to determine whether the fall in household size is a real phenomenon, unlikely as that is. Since the 1993 and 1988 household size estimates are reasonably close, it is more likely that decline in 22