Investigating the Impact of the Inverse Bullseye Effect on Interpretations of the SPC Categorical Convective Outlook

Abstract

Risk communication is a vital and growing research area in the field of meteorology. One of the most common graphics for probabilistic risk communication of severe weather is the Storm Predication Center (SPC) Categorical Convective Outlook, variations of which can be found across local and national news, governmental and commercial websites, and official and unofficial social media pages. The Convective Outlook’s widespread use as a tool to communicate to experts and non-experts alike has prompted the implementation of a multitude of studies seeking to understand its effectiveness, including investigations into its color scheme and category names in both English and Spanish. This study adds to the existing body of work by examining the impact of the Inverse Bullseye Effect (IBE), the negative impact that being located outside of the zone of highest risk has on individuals’ risk perceptions. Under the influence of the IBE, an individual located in an Enhanced risk area could perceive their risk as lower if a Moderate risk was depicted and higher if a Moderate risk was not depicted (thus making Enhanced the highest risk category on the map). The first goal of this work was to establish with what frequency tornadic events occur outside of the maximum threshold area (e.g. the Moderate contour area when the Moderate risk was the highest threshold for the day). This was done by intersecting Tornado Report points from the SPC’s SVRGIS database with 2000 UTC Categorical Convective Outlooks issued between 2015 and 2023. Results indicate that approximately 50% of weak (EF0 and EF1) tornado reports occurred outside of the maximum threshold area during this period, while the frequency of significant tornado reports occurring outside of the maximum threshold area varied between 15% and 55%, depending on the maximum threshold present. This work also found that tornado reports occurred outside of the maximum threshold area more frequently when the area was small and when the highest threshold was not driven by the tornado risk. The second and third goals of this work were to determine if the IBE had an impact on risk perceptions held by members of the public and, if so, whether the addition of a verbal or numeric reminder statement indicating that severe weather can occur outside of the maximum threshold may reduce the impact. These questions were investigated using responses to a set of six questions related to the Convective Outlook that were included in the 2025 edition of the Severe Weather and Society Survey. Participants were randomly assigned one of six mock SPC social media posts with varying combinations of Convective Outlook maps (with either Moderate as the maximum threshold or Enhanced as the maximum threshold) and reminder sentences (No Reminder, Verbal Reminder, or Numeric Reminder), with the same location within the Enhanced region marked on each, and were asked to indicate their estimated probability both verbally and numerically. Results indicate that the IBE did have a slight impact on both the numeric and verbal estimations of likelihood indicated by the participants, and the reminder sentences had little impact on these estimates when included.