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Benefit-Cost Analysis: Measuring Benefits

Benefit-Cost Analysis: Measuring Benefits. The focus of BCA is the total economic value (TEV) of the change in social wellbeing from a project/policy. Concretely: the sum of all relevant WTPs or WTAs for the change

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Benefit-Cost Analysis: Measuring Benefits

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  1. Benefit-Cost Analysis: Measuring Benefits

  2. The focus of BCA is the total economic value (TEV) of the change in social wellbeing from a project/policy • Concretely: the sum of all relevant WTPs or WTAs for the change • If a change matters to any individual at any current or future time it should be included in an economic assessment • Not typically focused on TEV of the stock of natural capital: • all-encompassing measure of the economic value of any environmental asset WTP: willingness to pay WTA: willingness to accept Pearce et al. 2006, chp. 6; Revesz and Stavins, 2007

  3. Conceptual model of value • WTP: the maximum amount of money an individual would pay to attain an improvement in the environment • WTA: the minimum compensation an individual demands to tolerate a loss of environmental quality

  4. Appropriateness of WTP or WTA depends on the baseline allocation of the property right. • Does the individual currently have some right to the good/service? • Yes WTA, i.e. to give it up • No WTP, i.e. to obtain • Sometimes WTP ≈ WTA, but not always • WTP <= ability to pay • If WTP ≠ WTA, typically WTA>=WTP • loss aversion, endowment effect

  5. Several important assumptions are implicit in the focus on WTP/WTA • Does not require actual payment • Human-centered/anthropocentric • Represents preferences of the individual (not the group) • Potential information problem Keohane and Olmstead (2007, pp. 33-37)

  6. The type of benefit to be measured has implications for the estimation approach (version 1) Kopp et al. 1997

  7. The type of benefit to be measured has implications for the estimation approach (version 2) A taxonomy of value from environmental assets Total economic value Pearce et al. (2006, Chp. 6)

  8. All benefits stem from either use or non-use values • Use value: the benefit of physically using or “consuming” an (environmental) good. • Non-use value/“passive use”: the benefit or pleasure derived from the knowledge that an (environmental) good exists without using it. • Types: • Existence value: altruistic value from preserving some amenity • Bequest value: value based on perceived value to future generations. • Option value: value from preserving the opportunity of future use • Can only be assessed using stated preference (survey) techniques

  9. All valuation tools elicit preferences that are either (1) explicitly stated, or (2) implicitly revealed • Stated preference (SP) techniques: • based on questionnaires given to respondents and which elicit the respondent’s WTP (or WTA) for use and/or non-use values(Pearce et al. 2007) • E.g. contingent valuation (CV), choice experiments, etc. • only way to estimate non-use values • Revealed preference (RP) techniques • use market information or behavior to estimate the value of a good not directly traded in a market. • E.g. hedonics, production function, etc. • Key ideas: bundled goods + “behavior trail” • Limited to estimating use value. (Pearce et al. 2007)

  10. Non-use values have been controversial at times but are recognized by U.S. courts • D. C. Court of Appeals: State of Ohio v. Department of the Interior (880 F.2d 432 (D.C. Cir. 1989)) • Ohio and others sought review of the Dept. of Interior’s natural resource damage assessment rules (under CWA & Superfund). • Court upheld inclusion of passive-use if it could be reliably measured. • Passive use losses were compensable (CWA/Superfund). • Ranking of assessment approaches with CV at the bottom was unwarranted.

  11. The type of benefit to be measured has implications for the estimation approach (version 2) Arsenic Hells Canyon Exxon Valdez VSL Chesap. Bay Pearce et al. (2006, Chp. 6)

  12. Revealed vs. Stated Preference methods: “Myth of market prices” (Fullerton & Stavins, 1998) • Myth #3: “when non-market solutions are considered, economists still use only market pricesto evaluate them” (p. 434) • “True enough, economists typically favour using market prices, whenever possible • …because these prices reveal how members of society actually value the scarce amenities and resources under consideration.” (p. 434) • BUT: BCA “cannot rely exclusively on market prices.”

  13. Valuation methods roadmap • A. Stated preference (SP) • Contingent valuation (CV) • Choice modeling • B. Revealed preference (RP) • Hedonic pricing (prices, wages) • Property value • Wage rates • Defensive behavior • Travel cost • Cost of illness (COI) • Materials damage (maintenance, repair, replacement)

  14. Stated Preference (SP) • John Krutilla (1967): “When the existence of a grand scenic wonder or a unique and fragile ecosystem is involved, its preservation and continued availability are a significant part of the real income of many individuals.” • SP:Estimates based on direct questioning (survey instruments) to elicit individual valuation for environmental changes • Can capture use & non-use value. • The only option for non-use value • Controversial

  15. Stated Preference: Contingent Valuation (CV) • Directly ask subjects via a survey about their WTP or WTA • “Contingent” because solicited valuation is “contingent” (dependent or conditional) on an (hypothetical) outcome.

  16. Steps of a stated preference study (Pearce and Özdemiroglu, 2002)

  17. Structure of the CV survey. (Pearce and Özdemiroglu, 2002)

  18. Potential pitfalls Real, incentives Lack of budget constraint % of respondents at this value or lower “cumulative density” Oath Hypothetical Hypothetical bias Protest Jacquemet et al. 2011

  19. Stated Preference: CV • Advantages • simple, direct and easily understood, broad applicability (can assess non-use value) • Disadvantages/sources of controversy • Can be expensive and time consuming • Hypothetical setting and choice • May be difficult for individuals to value environmental goods and services that they are not used to exchanging like private goods. • Lack of a strong incentive to tell the truth. • Salience of budget constraint uncertain • Response is only as “informed” as the respondents • Respondent may be expressing a value on something other than the intended element • The scenario or the valuation process • A warm glow from giving • Environmental quality in general • The wrong attribute: e.g. health effects of air instead of visibility • Subject to cognitive anomalies: embedding effect (e.g. 1 versus many species), order effect Environmental Economics : http://www.env-econ.net (2005) Ecosystem Valuation: www.ecosystemvaluation.org (2010)

  20. CV example: ExxonValdez • Industry complaints re: CV lead to blue ribbon NOAA panel chaired by K. Arrow and R. Solow. • Non-use value loss estimated using CV by Carson et. al, 2003 http://en.wikipedia.org/wiki/Exxon_Valdez_oil_spill http://response.restoration.noaa.gov Ran aground Prince William Sound 1989

  21. Exxon Valdez CV survey instrument • developed over 18-months • face-to-face, national sample • valuation scenario: • described the damages caused • established a referendum market for eliciting the respondent’s value • preventing a future accident that would cause an equivalent amount of damage in the Prince William Sound area • display cards, photographs, and maps were shown to the respondents to supplement verbal information Carson et al. (2003)

  22. Example design issues: • Designed to ensure that respondents do not answer a different question than the one they are asked, whether by • forgetting about their budget constraints or by • letting Prince William Sound stand for all oil spills or even all environmental damage.

  23. WTP Question & Results • The WTP question • Discrete-choice referendum elicitation format to ask whether the respondent would vote for the program if it cost a specified amount that would be paid by a one-time federal tax payment. • (Original study) lower bound on the estimated aggregate lost passive use values: $2.8 billion (1990 dollars). • multiplying the number of U.S. households by the estimate of median WTP

  24. Roadmap progress…. • A. Stated preference • Contingent valuation • Choice modeling • B. Revealed preference • Hedonic pricing (prices, wages) • Property value • Wage rates • Defensive behavior • Travel cost • Cost of illness (COI) • Materials damage (maintenance, repair, replacement)

  25. B. Revealed Preference • Depends on a relationship between a market and non-market good. • Behavior trail • Estimate the market “footprint” of non-market goods (bads) (Russell 2001) • For use value only

  26. Revealed Preference Methods Adapted from Boyle (Chp 8 in Champ et al. 2003)

  27. Revealed Pref: Hedonic Pricing Methods • Idea: if the price of something is related to multiple characteristics, look at the differences in prices to assess value buyers place on one of those characteristics. • Key concept -- Bundled goods: People value goods based on a bundle of attributes. (Couling, 2001) • Hedonic property value method • Real estate attributes: • Property, structure, landscaping • Additional “bundled” characteristics: schools, crime level, open space, environment • Hedonic wage method • Job attributes: • tasks completed • bundled: workplace community, workplace safety For overview see Taylor (Chp 10) in Champ et al. (2003)

  28. Hedonic Property Pricing Model Approach: statistically break down the value of a good into its component parts to isolate the value of the environmental attribute. This equation is linear but could alternatively be modeled as semi-log, double log, quadratic, etc. (see Taylor 2003) • P: housing price • H: structural and property characteristics • bedrooms, lot size, … • N: neighborhood characteristics • median income, school quality, …. • L: location characteristics • level of the environmental amenity • ε: error term for unobservables MWTP for the env. amenity Can use to evaluate amenities and/or disamenities Bruegel: The Triumph of Death

  29. Hedonic Property Value Example Leggett and Bockstael (2000) • Estimate the value of water quality in Chesapeake Bay • Water quality: reported faecal coliform levels (affects utility from recreational use) • Result: 1 unit (count/ml) increase in median annual concentration of pollution  property value falls by $5,000.

  30. Ford Pinto memo

  31. Hedonic wage method US Bureau of Labor Stat. (2002) Timber cutter mortality: 118/100,000 > 26 times that of the average U.S. worker • Estimate value of increased risk of on-the-job mortality (Value of a statistical life—VSL). • Wage rates are higher for those willing to accept riskier jobs (all else equal). • Idea: Wage differential between two jobs differing only in risk of death provides an implicit VSL • Elevated wages: “When the crabbing is good a crewman can earn upwards of $1,000 a day. Many timber fellers earn upwards of $60,000 working a nine- or 10-month year.” • Valuation of occupational risk then applied to a setting of environmental risk (benefits transfer) Per 100K CNNMoney.com, 10/13/03

  32. How much is your life worth? Stephen Colbert, The Colbert Report: The Word – “Priceless” http://www.colbertnation.com/the-colbert-report-videos/176175/july-14-2008/the-word---priceless

  33. EPA on VSL What Does it Mean to Place a value on life? • “The EPA does not place a dollar value on life, but the Agency does try to estimate the benefits from reducing the risk of death from environmental contaminants. .. • For benefit-cost analysis, the question is: How do people value, in dollar terms, this small (but important) reduction to their risk of dying? The process of valuing risk – also known as the process of valuing "statistical life" – does not produce an estimate of the value of life itself. “ What is the "Value of a Statistical Life"? • The "value of statistical life (VSL)" refers to the aggregate estimated value of reducing small risks across a large number of people. It is based on how people themselves would value reducing these risks Source: http://yosemite1.epa.gov/ee/epa/eed.nsf/pages/MortalityRiskValuation.htm

  34. Estimating benefits of reducing deaths • For a risk not currently incurred: • VSL = $WTA/ Δp here WTA is willingness-to-accept increased risk • For a risk currently incurred: • VSL = $WTP/ Δp here WTP is willingness-to-pay to reduce risk • E.g. if individuals demand $4 to accept an increase the risk of death of 2x10-6 (that is by 2 in a million) then (using $WTA = $4 and a change in risk Δp=2x10-6). • VSL = $WTA/ Δp = $4 / (2x10-6) = $2 million

  35. Cropper et al. 2011

  36. VSL • Not intended to reflect the intrinsic value of a life. • Rather: convenient, imperfect, one-size-fits-all measure of individuals’ demand for risk reductions (in small units, e.g. millionths). • Its estimation and its use are usually in units of 10-6 (changes in the probability of death in the “millionths”) • A VSL of $7M implies that an individual would be willing to pay $7.00 to reduce their risk of death by 10-6 • If a policy reduced the mortality risk of everyone in the U.S. by 10-6, then with a VSL of $7M (or $7 x 106), the benefit could be estimated by: • (Δp x VSL ) x (number affected) • (10-6 x [$7x106] ) x (3x108 ) • $7 x 3x108

  37. General issues with hedonic methods • Models generally assume that households/individuals have perfect information about attributes of the property/job. • Simultaneity: causality • Property: causality between env. quality and price (e.g. higher quality leads to higher price, larger tax base, more money for env. quality). • Wage: causality between risk and wages can go both ways (e.g. higher wage to compensate for air pollution but high wage attracts more workers leading to change in air quality)

  38. Revealed Preference: Defensive Behavior • Estimate willingness to pay to reduce a “bad” by looking at avoidance expenditures made to reduce the risk or the impact of the bad. • E.g. water quality: when faced with water of dubious quality how much do individuals spend to improve their drinking water (expenditures: filters and bottled water)

  39. Revealed Preference: Travel cost • Estimate value of an amenity (e.g. park) by treating the costs incurred to experience it as its “price”. • Idea: travel and the recreational area are complements (consumed together) • Information needs (gathered via survey): • # of trips taken (by indiv’ls/households) to a particular site in a year • their travel cost to that site • Monetary (out-of-pocket cost: gas, hotel, etc) • Opportunity cost of leisure time (shadow value of time constraint, e.g. 1/3 to 1/2 wage rate)

  40. Travel cost example • Focus on the behavior of the Worthingtons, a single family who lives a given distance away from a free public park. • Survey work  Worthingtons visits this park an average of four days/year. • Estimate their travel costs to go from their home to the park and return. • cash travel cost (gas, wear and tear on the car, food, etc.) is $18 per trip • round trip takes one hour each way (need to put a value on the time spent traveling) • tricky: need value foregone, in terms of salary or other income, by spending this time traveling rather than working. • Empirical work  ⅓ to ½ of the wage rate; • assume their travel time is worth $8.00 per hour Roundtrip cost of travel time: $8 * 2 = $16 • Price the Worthingtons “pay” for each visit to the park is the total cost of the trip: $18 + $16 = $34.

  41. Travel cost example: Calculating the value • Suppose: there are only three other families within range of the park • Surveyed travel costs for all four: Assume: • each family is identical accept for their travel cost (can treat the table as any individual family’s demand schedule) • demand is linear (a straight line). (Worthingtons) • Calculate (chalkboard exercise—review of plotting demand curve, calc. of benefits, consumer surplus) • For each individual in this “world” calculate • (Gross) benefit of the park (given their observed number of visits) • Net benefit of the park • Then sum these values to find the aggregate (1) benefit, and (2) net benefit of the park. • Have we estimated the complete value of the park to these families? What component of the complete value have we estimated? Use value or non-use value? Was this stated or revealed preference?

  42. Travel cost caveats • in practice much more complicated • Families will differ in terms of many factors (not just in travel costs) • income levels, presence of alternative parks and other recreational experiences available to them, etc. • Solution: collect large amounts of data on many visitors; statistically sort out various influences on park visitation rates.

  43. Travel cost example: Hells Canyon The Situation • Hells Canyon on the Snake River (separating Oregon and Idaho) • spectacular vistas, outdoor amenities, important fish and wildlife habitat • economic potential as a site to develop hydropower • Generating hydropower  damlarge lakesignificantly and permanently alter the ecological and  aesthetic characteristics of Hell Canyon.  The BCA Challenge • 1970’s: Env. economists from Resources For The Future in Washington, D.C. • asked to develop an economic analysis to justify preserving Hell Canyon in its natural state http://www.fs.fed.us/hellscanyon/ *Example from: http://www.ecosystemvaluation.org/travel_costs.htm http://upload.wikimedia.org/wikipedia/commons/3/36/OR_hells_canyon.jpg

  44. Travel Cost: Hells Canyon (cont’d) The Analysis • Economic value of project: Net economic value (cost savings) of producing hydropower at Hells Canyon was $80,000 higher than at the "next best" site which was not environmentally sensitive. • Task: Estimate the economic value of losing the environmental amenities of Hells Canyon: Travel cost survey valuation: $900,000 • TCS was low-cost/low precision • But researchers did not attempt to strongly defend the "scientific" credibility of the valuation method/results. • Emphasized that, even if the "true value" of recreation at Hell Canyon was ten times less (i.e. $90k), it would still be greater than economic payoff from generating power there ($80k). The Results • Based largely on the results of this non-market valuation study, Congress voted to prohibit further development of Hell Canyon.

  45. Travel cost example: South African game reserves (Day, 2002) • What would be the lost welfare to domestic visitors to four game parks? • Data: survey of 1,000 visitors • Demonstrates the effect of site substitutes. “Mr. Shuffles” TorstenBlackwood/AFP/Getty Images.

  46. Revealed Preference Methods Adapted from Boyle (Chp 8 in Champ et al. 2003)

  47. Revealed versus stated pref. Econometrics lab, UCB (http://elsa.berkeley.edu/eml/qca_reader/9.combin.pdf)

  48. Optional additional slides

  49. Revealed Pref: Cost of illness • Used to estimate benefits from policies which result in increased health • Easy to understand • Not grounded in consumer choice and welfare theory (in contrast to other methods) • No estimate of marginal pricing or surplus

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