To answer our question, a constructivist approach is adopted. Assessing and managing all kinds of risk is a challenging task but this is especially the case in those risks pertaining to human health which are largely dealt with in the public domain. Because these concerns do invoke public discourse, much attention has been paid to the differences, if any, between expert and public perceptions and assessments [11] . For twenty years or more, constructivist analyses have brought to the fore the importance of prior social, cultural, institutional and political factors that shape and are embedded in both lay and expert risk assessments (see [12] ). Lay people and experts use similar cognitive processes with both falling prey to errors from anchoring, overconfidence and the gambler's fallacy (see [13] ) Attention has also turned to the perceptions and assessments of experts themselves. Van Zwanenberg and Millstone [12] comment that the construction of scientific claims can inform risk assessments. Furthermore, a "coherent realm of expertise" may not exist, as Haggerty [14:201] points out with respect to crime risk. He adds that expert opinion about crime risk is incredibly fractured with there being differences in professional opinion with respect to dimensions of high-profile risks as well as the nature and efficiency of crime prevention. Sjoberg [15] also points out that there is likely to be a whole range of expertise and this range is not well-articulated in many risk perception studies. If, therefore, there is this range of expertise, why should we expect expert opinions to converge, although overconfidence in technical and medical assessments may exist (but see [16] )? In fact, we shall note certain biases in expert opinion.