A method for product guidance in a stretch blow molding and/or filling system for bottles, and a corresponding production system are described. Preform parameters of preforms provided for stretch blow molding are measured in an automated manner and initial data acquired in the process is stored. Bottle parameters of the blown empty bottles and/or subsequently filled bottles are measured and machine error states are optionally detected. Results data acquired in the process are individually associated with the preforms and stored. At least one lead-out criterion applicable in the downstream production operation is calculated for deciding whether or not to lead out faulty preforms or bottles, based on the initial data and results data. The lead-out criterion is additionally updated in an automated manner while taking into consideration the acquired initial data and results data.