The importance of being informed: Experimental evidence on demand for environmental quality

To what extent does information affect the demand for environmental quality? A randomly selected group of households in an Indian city were informed whether or not their drinking water had tested positive for fecal contamination using a simple, inexpensive test kit. Households initially not purifying their water and told that their drinking water was possibly contaminated, were I I percentage points more likely to begin some form of home purification in the next eight weeks than households that received no information. They spent $7.24 (at PPP) more on purification than control households. By way of comparison, an additional year of schooling of the most educated male in the household is associated with a 3 percentage-point rise in the probability of initial purification, while a standard-deviation increase in the wealth index is associated with a 12 percentage-point rise in this probability and an $11.75 rise in expenditure. Initially purifying households that received a no contamination result did not react by reducing purification. These results suggest that estimates of the demand for environment quality that assume full information may significantly under-estimate it. (c) 2007 Elsevier B. V. All rights reserved.