Hydraulic ram pumps and Sling Pumps

OP 32-EAnnex 6: Example of a behaviour studyThis study was developed in two stages. In 1988, families in Kerala State in India were surveyed abouttheir willingness to pay for household connections to a piped water supply system and to establishfuture trends in their behaviour, using the Contingent Valuation Method. In 1991, the same familieswere surveyed again, observing their actual behaviour, to see if they behaved as they said they would(benefit revelation), and to ascertain the accuracy of the predictions.1988 study: contingent valuationIn both A and B communities, households were asked about their willingness to pay if the reliability ofthe service was improved. The bidding game was used to estimate WTP of the head of the household.The results were:• Monthly tariff and connection costs were determinants of WTP. An increase of 10 rupee in themonthly tariff would cause a fall of 27% in the probability that a family would connect: while thesame increase in the connection cost would cause a probability decline of 82%.• The decision to connect had a positive correlation with high income levels, assets and schooling.• Families living in water scarce zones were probably more willing to connect than those living inwater abundant zones• A more reliable service was an important factor for those who were connected at the time of thesurvey. It was not an issue for those who were not connected.1991 study: actual behaviourThis study tried to re-survey the same families of the 1988 study. There was a sample change bywhich they lost 25 of 200 households in B communities. However, the change affected all incomegroups equally, and the survey retained the original income distribution. Criteria used to establish thevalidity of predictions were:• The right proportion of connectors, without considering if the behaviour of the families wasaccurately described• Analysis of whether families behaved as they said they would, considering three elements:1) the proportion of the sample whose actual behaviour was correctly predicted (gross accuracy),2) the proportion of those families who connected, whose decision was correctly predicted(specificity),3) the proportion of families who said would not connect, and did not (sensitivity).To answer to these questions the authors of the study compared the results of both 1988 and 1991studies. The most important results were:• 14.9% of the families did connect (22/148), while the authors’ predictions said that 14.2 % of thefamilies would connect. The prediction was accurate.• 91% of the families ((15+120)/148) behaved as they said they would (gross accuracy).• The percentage of those predicted to connect who actually did connect was 71% (15/22)(specificity).• 94% of those predicted not to connect (120/127) did not connect (sensitivity).• 75% of non-connectors indicated inability to pay the connection cost as the first reason for notconnecting. The authors predicted in 1988 that this would be the most important reason for nonconnectors.• All the families who had connected in 1991 were dissatisfied with the reliability of the system,while only 13% of non-connectors gave this as a reason for their decision not to connect.Benefit TransferThe study tried to predict the behaviour of the families in type B communities in water scarce zones byusing behavioural models to extrapolate from results in type A communities with the same problem(water scarcity). Although the communities are similar the results were disappointing, and the use ofbehavioural models to predict behaviour in B communities gave completely inaccurate results. Forexample, authors predicted that 76% of families in sites B would connect while only 16.6% of them64