1. Use of mean substitution instead of median:
a. For land size, most households have no land so the median may end up as zero. However, that variable is the result of two questions, whether the household owns agricultural land and if so, what the size of the land is. The missing and unknown responses for land size are for those with land from the first question and so the median should not be zero.
b. For number of household members per sleeping room, the distribution is not very skewed so the mean and median should produce similar results. In any case, the missing data would come from number of sleeping rooms, not number of household members, and almost all households have less than 10 sleeping rooms.
2. The use of integers for number of members per sleeping room is for convenience when tabulating the frequency distribution and means of wealth by number of members per sleeping room to check on the results. Alternatively, a continuous variable can be and has been used in a few surveys, but hardly any difference in results has been found.
3. One should remember that the wealth index is not an absolute measure of net worth, and is derived from a sample of households, and as such is subject to sampling variance and non-sampling error. Additionally, the wealth index also depends to a small extent on the assets, dwelling materials, amenities and other indicators chosen for the survey. Small differences in household wealth score due to handling of continuous variables will not invalidate the relative position of households. However, some non-linearity is taken into account of these variables for number of farm animals by type, and will be tried for land size as well.