This paper analyzes the short-term dynamics of issue ownership and its effect on electoral choice. We hypothesize that voters who change their mind with regard to the party they deem most competent to handle the top issue are more probable to change their vote choice, than those who do not change their evaluation of competence. Second, we claim that the impact of a change in perception of party issue competence increases with the electoral strength of the party benefiting from this change. The analysis is based on data from a Rolling-Cross-Section with a panel component carried out in the 2011 Swiss Election Study. The results show the expected effects of change in issue competence assessment and the conditional role of party size.