- **Stated preference** methods are frequently applied in **environmental valuation** to estimate economic values of policies, goods, and services that cannot be valued otherwise.
- Stated preference methods face **validity challenges**.
- Valid value estimation requires **sufficient information** provision about the good being valued.
- Still unclear **what formats of information** and **how much information** are optimal for valid preference elicitation.
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- Discrete choice experiments are increasingly used in environmental valuation
## Motivation (2)
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- Too **much information** may increase survey **complexity**, leading to respondents being overburdened with it and producing less consistent choices.
- Too **little information** may lead respondents to **not** being able to make an **informed choice**.
- Valid preference elicitation depends not only on the provision of information, but also on the **appropriate processing and recall** of the information by the respondent.
- **Voluntary information** allows the respondents to gather required information if needed.
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- Validity is debated due to potential influence of information provision on welfare estimates
## Literature
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- There is **little research** on the effects of **voluntary information provision** on choice behavior and information recall.
- In their study, **Tienhaara et al. (2022)** surveyed preferences for agricultural genetic resources, allowing respondents the option to access detailed information on the valued goods prior to preference elicitation.
- Similarly, **Hu et al. (2009)** offered respondents the opportunity to access voluntary information about genetic modified food before participating in a choice experiment.
- Both studies conclude that, on average, respondents who retrieve voluntary information
have **larger willingness to pay** for the good to be valued.
- Their study design, however, does not allow comparing the voluntary information retrieval to a version where the additional information was shown obligatory.
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## Research Contribution
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- Our study explores the impact of additional obligatory and voluntary information on stated preferences using an exogenous split sample approach with three treatments.
- We investigate the effects of information treatments on survey engagement, information recall, consequentiality, and stated preferences, similar to Welling et al. (2023), expanding our understanding of treatment effects.
- We test who choose additional information and to what extent they have different preferences than respondents who do not choose aditional information.
- We employ DCE to test influence of additional information on urban heat island on the valuation of UGS
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## Research Questions
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1. How do obligatory and voluntary information treatments affect **survey engagement**, **information recall**, **consequentiality**, and **stated preferences**?
2. Do **socio-demographic** variables or natural **connectedness** influence the decision to **access voluntary information**?
3. Do **survey engagement**, **information recall**, **consequentiality**, and **stated preferences** differ between respondents who **access voluntary information** and those who do not?
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## Discrete Choice Experiment
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- To investigate the research questions, we use data from a **discrete choice experiment (DCE)** on naturalness of urban green spaces.
- The survey is an exact **replication** of the choice experiment of **Bronnmann et al., (2023)** and differs only in the information provided to the respondents.
- In the DCE, respondents were asked to imagine possible **changes** to their **most frequently used UGS**.
- This **restructuring** involved adjustments to the UGS’s **naturalness** and changes to the **walking distance**.
- The associated **costs** of this restructuring were intended to be integrated into monthly **rental payments**.
- Participants in the DCE were presented **ten** randomly assigned **choice cards** with a choice between **two alternative programs** for the renovation of the UGS and the **current status quo**.
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## Choice Card
## Research questions
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1. Who chooses optional information?
2a. How does an information treatment about urban heat islands affect survey engagement (interview time, cc time), quiz questions, and consequentially?
2b. How are these factors influenced by voluntary information access?
## Treatment (Information provision)
- Short info text about the effect of **natural urban green spaces** on urban **heat islands**.
- **Optional video** with the almost the same information.
3. How do the different treatments affect the WTP for urban green spaces in the choice experiment?
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4. Do people who choose **voluntary** information have a different WTP/preferences?
## Treatment (Quiz)
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**Seven quiz questions** with strict reference to the previously provided information.
## Discrete Choice Experiment
Example Questions:
- Setting: Restructuring of individually most visited UGS in terms of proximity and naturalness financed via incidental costs
- Main attribute of interest here: naturalness defined by five-level graphical scale ▶ Range: hardly natural to very natural
- Three survey rounds; paper by Bronnmann et al. (2023) based on round 1 & 2, our paper is based on last survey round from February 2023
1. Which of the following statements are correct?
## Choice Card
- The temperature difference between the city and the surrounding area can be up to 10
degrees Celsius. (true/false)
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## Treatment Groups
2. According to the information provided, which of the following properties influences
the temperature in the city?
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- The proximity of green spaces to nature (yes/no)
- Light pollution in the city (yes/no)
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## Case A
## Treatment (Self reference)
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To what extent do you agree or disagree with the following statements?
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1. I am limited by high temperatures in the city during the summer. (Strongly agree - Strongly disagree)
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2. The city should do more to avoid heat islands. (Strongly agree - Strongly disagree)
- Natural Relatedness Index: Measure derived from 21 items on **connectedness to nature**.
- Quiz: Evaluation of the quiz we gave to everyone after the DCE.**->Information recall**
- Timings: We saved the net interview time and the mean Choice Card time.-> **Survey engagement**
- **Consequentiality**:
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-- To what extent do you believe that the decisions you make will have an impact on how the green spaces in your neighbourhood are designed in the future?
-- To what extent do you believe that the decisions you make will affect whether you have to pay a contribution for urban greening in the future?
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## Methods
- Logit regression (voluntary information access):
