Comments on Comments on Visibility Valuation Section (9.3.5) - - PowerPoint PPT Presentation

Comments on Comments on Visibility Valuation Section (§9.3.5) Visibility Valuation Section (§9.3.5)

• f the First External Review Draft of EPA’s
• f the First External Review Draft of EPA’s

Integrated Science Assessment for Particulate Matter Integrated Science Assessment for Particulate Matter

Public Comments Session Public Comments Session CASAC Meeting CASAC Meeting April 1-2, 2009 April 1-2, 2009

• Dr. Anne E. Smith, Ph.D.

Vice President Comments prepared on behalf of UARG

Main Points in My Written Comments

• 1. VAQ Preference Studies do not provide a valid basis for

identifying the public’s preference for a visibility standard

Sole focus of rest of my oral comments

• 2. Two new visibility studies reinforce evidence that results
• f both preference and valuation studies are

“contaminated” by people’s concerns about healthfulness

• f air.
• 3. The new property value study, Beron et al. (2001), cannot

justify its claim that it has separated health values from aesthetic values.

• 4. The ISA should acknowledge another new visibility

valuation study, Smith et al. (2005, 2006), which provides additional relevant evidence about the interpretation of visibility WTP estimates based on the contingent valuation method.

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VAQ Preference Studies

• Method:

Ask a sample of people to look at photographs of their local area of residence

– Range of VAQ levels shown in a set of photographs of same vista – Ask them to report whether each VAQ level is “acceptable” or “unacceptable”

• Results:

Percent who say “unacceptable” increases as VAQ in photographs worsens

• Interpretation by Authors (and EPA):

VAQ level that 50% of people say is “unacceptable” should be VAQ visibility standard.

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0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Percent "Unacceptable"

50% Say VAQ is “Unacceptable”

Abt Results

Example of One VAQ Preference Study: Washington DC (Abt Associates, 2001)

8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44

Deciview

Implied Range for a VAQ Standard

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Percent "Unacceptable"

CRA Study’s “Test 1” Was Able to Replicate Abt Results

• - Same Range and Ordering of VAQ Were Shown

100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44

Deciview Abt Results

CRA “Test 1” Results: Replicated Abt’s

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CRA “Test 1” Results (same VAQ range as Abt)

CRA Study’s “Test 2” Used Only Photos with VAQs Deemed Acceptable by >50% in Original Survey

Percent "Unacceptable"

100% CRA “Test 2” Results: 90% Highly “acceptable”

VAQs in original design

80%

become “unacceptable”

70% 60% 50% 40% 30% 20% 10% 0%

“Test 2” showed only photos with 27.1 dv or less

(but in same order as original design)

8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44

Deciview

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CRA Study’s “Test 3” Added Two Photos with Higher

Percent "Unacceptable"

Deciview Levels Than Highest in Original Survey

100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

Deciview CRA “Test 2” CRA “Test 1”

CRA “Test 3” Result: “Unacceptable” VAQs in original design become “acceptable”

8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44

CRA “Test 3” included 2 photos with higher deciviews than highest in original design

(42 dv and 45 dv events do occur on occasion)

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Conclusions on VAQ Preference Study Method VAQ preference study method is not a scientifically valid basis for setting a visibility standard

• VAQ Preference Studies do not reveal a “credible” or

“enduring” judgment about what people’s “own eyes tell them is the cutoff between acceptable and unacceptable VAQ.” 1/

• CRA’s research indicates that the preference study method

induces people to judge acceptability entirely in relative terms – This calls into question whether an absolute standard of acceptability for VAQ even exists

1/ Quote from the original VAQ preference study, Ely et al., 1991, p. 3

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