Chasing the unbiased willingness to pay: Using an integrated contingent valuation survey in estimating the non-market value of rubber plantation ecological restoration programs in China

Abstract

The rubber expansion in Asian countries has led to various environmental problems. To smoothly promote the ecological restoration programs, an essential premise is that the local government must consider public attitude and understand the public willingness to pay (WTP) for the programs. In this study, we employ an integrated contingent valuation (ICV) survey to evaluate the citizen’s WTP of implementing rubber plantation ecological restoration (RPER) programs in Hainan, China. Considering three types of the respondents’ WTP data (interval truncated, merged, and point data), we adopt the Point and Interval Data (PID) model to estimate the determinants of WTP and calculate the non-market value with the comparison of the Tobit model. Results show that the mean value of WTP for the RPER program is 178 yuan per year, and the total non-market value throughout the province is worth approximately 1.839 billion yuan per year after controlling the regional differences. We also find that the respondents’ WTP has a significant regional difference, in which Danzhou has the highest WTP, followed by Haikou, Wanning, and Sanya. Age has a significant negative effect on the WTP for the restoration program, whereas the factors such as education, family burden, income, and residents’ environmental knowledge have a significant positive effect. Our findings add to the evidence that using improved estimation methods can generate diverse results, where neglecting the bias caused by the usual interval data model would lead to downward biased estimates.