Table 1.

Summary of data on populations included in the water filtration program carried out in Matlab, Bangladesh

	Pilot phase September 1999–December 2000 (16 months)			Full study January 2001–July 2002 (19 months)
	Sari	Nylon	Control	Sari	Nylon	Control
No. of villages	7	8	3	27	25	13
No. of individuals	11,267	15,418	18,461	44,429	44,496	44,194
No. of individuals in the study	4,131	4,477	4,416	14,709	15,748	15,662
No. of households in the study	737	726	749	2,750	2,750	2,750