Boxplot of scores for hazard importance by background (see also Table 3; n = 23 experts). Asterisks and circles indicate two types of outliers as standard practice in SPSS. Outliers are scores with values between 1.5 and 3 box lengths from the upper or lower edge of the box. The box length is the interquartile range (i.e. median 25% to 75% of values), while the horizontal line in the box indicates the median value.