Kelvin Balcombe and Iain Fraser, "Dichotomous Choice Contingent Valuation with a 'Dont know' Responses and Misreporting", Journal of Applied Econometrics, Vol. 24, No. 7, 2009, pp. 1137-1152. We employed two data sets in this paper. The first has previously been used by: Chambers, C. M. and J. C. Whitehead (2003). Contingent Valuation Estimate of the Benefits of Wolves Miinnesota, Environmental and Resource Economics 26, 249-267. The second was collected and used by: Samnaliev, M. Stevens, H., and Moore, T. (2006). A Comparison of Alternative Certainty Calibration Techniques in Contingent Valuation, Ecological Economics, 57, 507-519. The Chambers and Whitehead data (in the file cv-yes-no-data.txt) consist of two parts. One part is referred to as St Cloud, the other Ely. These names indicate the difference in location of data collection. An additional file (wolf-lim.txt) contains the original coding of the data undertaken in Limdep. This file provides information regarding the varibales to be used to test the importance of the dk responses. In the file cv-yes-no-data.txt, the data are ordered by row. The top row is the variable label. Each subsequent row is a response from a survey respondent. The Samnaliev et al.(2006) data (in the file samnal.txt) has variable labels in the first row and survey responses by row. The original survey instrument (02-3-14RecFeeSurvey3) as well as a document describing the coding of the data (Coding) are also included. Both .doc and .pdf versions are provided. All three data files are ASCII files in DOS format. They are zipped in the file bf-data.zip. Unix/Linux users should use "unzip -a". The additional files from the Samnaliev et al. paper are Coding.doc, Coding.pdf, 02-3-14RecFeeSurvey3.doc, and 02-3-14RecFeeSurvey3.pdf. These four files are zipped in the file samnaliev-files.zip.