The document is 2005 study by World Bank of selected slum areas of Nairobi, Kenya In response to the government’s request for technical and financial assistance for improving delivery of basic infrastructure service to the urban poor in Nairobi city. The official average household size in Nairobi’s slums. The based on observations from this study, this relatively low average household size is attributed largely to the split in families: a third of the households in our random sample (n=20) across the 5 settlements were split, with part of the household (not including extended family members) living in the city, and the rest living in the home village. Another factor contributing to the low average household size is the large number of single-person households.