Pick of the crop: understanding the choice of scientific and experiential evidence in Swiss pesticide discourse.

In political discourse, speakers use scientific and experiential evidence. Both types can inform policy making, yet little is known about when political actors turn to experiential evidence to back their statements. In this article, we examine factors that influence the selection of scientific and experiential evidence in political discourses. Using data from a quantitative content analysis, we assess the influence of (1) issue polarisation, (2) the statement's focus on either the problem or the solution, and (3) the actor's position on policy change on the type of evidence used in Swiss media discourse on pesticides between 2013 and 2022. Our results show that an increase in issue polarisation was associated with an increase in the use of experiential evidence. It also mattered whether evidence was used to describe problems or solutions. In both cases, scientific evidence was preferred, but experiential evidence was used more often when speaking about solutions. Whether speakers were proponents or opponents of policy change had no influence on the type of evidence used. These findings suggest that speakers generally considered scientific evidence more appropriate to support their statements than experiential evidence. However, with increasing polarisation, the reliance on experiential evidence over scientific evidence suggests a shift towards emotionally resonant narratives rather than rigorously validated knowledge. For the case studied, we conclude that while speakers are committed to evidence-informed policy making in principle, experiential evidence is at risk of being devalued and weaponised in polarised contexts.