一、Stated preference method

1. Introduction

• Stated preference methods 陈述偏好法—— Infer preferences from a person’s statement
• Non-use values cannot be estimated by revealed preference method, because people don’t take action for non-use value. Can only be estimated by stated preference methods.
• Use-values can be estimated by both stated and revealed preference methods. When use-values are complicated and it is hard to estimate each use-value, we can use stated preference method to estimate a total use-value.

2. Methods

• Contingent valuation 条件价值评估法
• Choice experiment 选择实验法

二、Contingent valuation

（一）Overview

• Basis: Estimate economic values for all kinds of environmental goods or services by directly asking people, in a survey, how much they would be willing to pay or willing to accept.【简而言之，直接问】
• Application: Can be used to estimate both use and non-use values, and mostly used for non-use values

（二）Steps

overview

Step 1: Identify the change in quantity or quality to be valued

• “Contingent”: contingent on the hypothetical scenarios presented【条件是由假定的情景确定的】
• The surveys usually present at least two possible outcomes：
  • One outcome is generally what would happen if no further action were taken.
  • The other outcomes are generally what might happen if we undertake a program/policy that would protect environment.