The present invention discloses a method for the online determination of a bulge/upset dimension xST and rivet head end position K of a rivet 3 with a length L in a punch rivet process with the help of a moveable punch 10 and a rigid die 20. The path covered by the punch 10 and the force applied by it are determined and evaluated online during the joining process. The quality characteristics of the joint connection are determined with the help of defined threshold values or a graphical evaluation of force/path data of the joining process.