Understanding the role of the forecast-maker in overestimation forecasts of policy impacts: The case of Travel Demand Management policies
Forecasting the impacts of a proposed policy is an important component of the transportation planning and decision making process. Although scientific tools are often used in transportation forecasts, biases and, more specifically, overestimations of the expected impact are often observed. This study explores the correlations between forecast-maker's characteristics and forecast bias creation and reduction. The study examines two transport-related policies aiming at the reduction of car use: telecommuting and carsharing. Both are Travel Demand Management (TDM) policies, which attract much attention from transport experts. We tested the extent to which the forecast-maker's beliefs about the policy at stake affected the forecast bias. We found that attitudes and beliefs associates not only with overestimation bias but also with its reduction over time. We also tested the extent to which the forecast-maker's affiliation, the performing institute and the publication type were correlated with the biases of the forecast and with the forecaster attitudes and beliefs. These characteristics are intuitively used by the forecast user as tools to assess the 'objectivity' of the forecast, but our analysis found no association between these characteristics and the forecast bias.
If you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.
As the access to this document is restricted, you may want to look for a different version under "Related research" (further below) or search for a different version of it.
Volume (Year): 45 (2011)
Issue (Month): 5 (June)
|Contact details of provider:|| Web page: http://www.elsevier.com/wps/find/journaldescription.cws_home/547/description#description|
|Order Information:|| Postal: http://www.elsevier.com/wps/find/supportfaq.cws_home/regional|
References listed on IDEAS
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Shaheen, Susan & Sperling, Daniel & Wagner, Conrad, 1998. "Carsharing in Europe and North American: Past, Present, and Future," University of California Transportation Center, Working Papers qt4gx4m05b, University of California Transportation Center.
- Brinkman, P. Anthony, 2003. "The Ethical Challenges and Professional Responses of Travel Demand Forecasters," University of California Transportation Center, Working Papers qt7vb2d17h, University of California Transportation Center.
- Brinkman, Anthony P., 2003. "The Ethical Challenges and Professional Responses of Travel Demand Forecasters," Institute of Transportation Studies, Research Reports, Working Papers, Proceedings qt9c3330tt, Institute of Transportation Studies, UC Berkeley.
- Kahneman, Daniel & Tversky, Amos, 1979.
"Prospect Theory: An Analysis of Decision under Risk,"
Econometric Society, vol. 47(2), pages 263-91, March.
- Amos Tversky & Daniel Kahneman, 1979. "Prospect Theory: An Analysis of Decision under Risk," Levine's Working Paper Archive 7656, David K. Levine.
- Mackie, Peter & Preston, John, 1998. "Twenty-one sources of error and bias in transport project appraisal," Transport Policy, Elsevier, vol. 5(1), pages 1-7, January.
- Baghestani, Hamid, 2008. "Federal Reserve versus private information: Who is the best unemployment rate predictor," Journal of Policy Modeling, Elsevier, vol. 30(1), pages 101-110.
- Sangho Choo & Patricia L. Mokhtarian & Ilan Salomon, 2005.
"Does Telecommuting Reduce Vehicle-miles Traveled? An Aggregate Time Series Analysis for the U. S,"
- Sangho Choo & Patricia Mokhtarian & Ilan Salomon, 2005. "Does telecommuting reduce vehicle-miles traveled? An aggregate time series analysis for the U.S," Transportation, Springer, vol. 32(1), pages 37-64, January.
- Marshall, Stephen & Banister, David, 2000. "Travel reduction strategies: intentions and outcomes," Transportation Research Part A: Policy and Practice, Elsevier, vol. 34(5), pages 321-338, June.
- Richard Boylan, 2008. "Political distortions in state forecasts," Public Choice, Springer, vol. 136(3), pages 411-427, September.
- Steininger, Karl & Vogl, Caroline & Zettl, Ralph, 1996. "Car-sharing organizations : The size of the market segment and revealed change in mobility behavior," Transport Policy, Elsevier, vol. 3(4), pages 177-185, October.
- David Laster & Paul Bennett & In Sun Geoum, 1999. "Rational Bias in Macroeconomic Forecasts," The Quarterly Journal of Economics, Oxford University Press, vol. 114(1), pages 293-318.
- Martin, Elliot & Shaheen, Susan Alison & Lidicker, Jeffrey, 2010. "Carsharingâ€™S Impact On Household Vehicle Holdings: Results From A North American Shared-Use Vehicle Survey," Institute of Transportation Studies, Working Paper Series qt0850h6r5, Institute of Transportation Studies, UC Davis.
- Tal, Gil, 2008. "Overestimation Reduction in Forecasting Telecommuting as a TDM Policy," Institute of Transportation Studies, Working Paper Series qt1qk959v1, Institute of Transportation Studies, UC Davis.
- Mackett, Roger L. & Edwards, Marion, 1998. "The impact of new urban public transport systems: will the expectations be met?," Transportation Research Part A: Policy and Practice, Elsevier, vol. 32(4), pages 231-245, May.
- Meyer, Michael D., 1999. "Demand management as an element of transportation policy: using carrots and sticks to influence travel behavior," Transportation Research Part A: Policy and Practice, Elsevier, vol. 33(7-8), pages 575-599.
When requesting a correction, please mention this item's handle: RePEc:eee:transa:v:45:y:2011:i:5:p:389-400. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Zhang, Lei)
If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If references are entirely missing, you can add them using this form.
If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.
Please note that corrections may take a couple of weeks to filter through the various RePEc services.