Resumen: The objective of the study is to investigate the effect of the oath script (HO) in an hypothetical Contingent Valuation survey in a Mediterranean country (e.g. Italy). Hence, there were conducted the CE surveys with three treatments: (1) CV without a cognitive task, (2) CV with a CT script, and (3) CV with a HO. The findings showed that the effectiveness of the HO script depends on the participants'' socio-demographic characteristics. For instance, it was found that the HO script could help to reduce the hypothetical bias for people who possess a high educational level in contrast with those people with low education and low income. Hence, the findings suggest that the oath script not only does not a guarantee the reduction of the hypothetical bias, but it also does not explain the mixed results found in the previous studies. Idioma: Inglés DOI: 10.17221/174/2015-AGRICECON Año: 2016 Publicado en: Agricultural Economics-Zemedelska Ekonomika 62, 8 (2016), 378-384 ISSN: 0139-570X Factor impacto JCR: 0.789 (2016) Categ. JCR: ECONOMICS rank: 197 / 347 = 0.568 (2016) - Q3 - T2 Categ. JCR: AGRICULTURAL ECONOMICS & POLICY rank: 12 / 17 = 0.706 (2016) - Q3 - T3 Factor impacto SCIMAGO: 0.564 - Economics, Econometrics and Finance (miscellaneous) (Q1) - Agricultural and Biological Sciences (miscellaneous) (Q2)