Recent research discovered that economic processes influence national averages of customer satisfaction. Using time-series data from Japanese and South Korean hospitals, we conducted principal component regression analyses to examine whether these findings are transferable to patient satisfaction. Our results reveal that aggregate income has a positive impact and economic expectations have a negative impact on patient satisfaction. Further analyses demonstrate that these strong economic influences make it difficult for hospital managers to use patient satisfaction scores to assess the performance impact of their customer-oriented actions. In order to improve performance evaluations based on patient surveys, we thus recommend managers to remove economic influences from time-series of patient satisfaction.