Educational large-scale assessment (LSA) studies like the program for international student assessment (PISA) provide important information about trends in the performance of educational indicators in cognitive domains. The change in the country means in a cognitive domain like reading between two successive assessments is an example of a trend estimate. The uncertainty of trend estimates includes sampling and linking errors, which are regularly reported in the PISA study. This article focuses on the linking error that assesses the variability in trend estimation regarding the choice of items. Since PISA 2015, the linking error estimation method has changed. This article compares the statistical behavior and the concept of the new PISA linking error and the PISA linking error utilized until PISA 2012. It turns out that the newly proposed linking error provides no generalization of the old PISA linking error but rather reflects different aspects of uncertainties and model error.