A method for controlling polymer viscosity quality in a compounding process of polymers using at least one extruder, wherein the compound at least partially comprises at least one thermoplastic material selected from the group consisting of: polybutylene terephthalate; polyethylene terephthalate; polyamide; polystyrene, the method comprising: a) at least one measurement step, wherein at least one influence variable affecting viscosity of the compound is determined by using at least one sensor; b) at least one prediction step, wherein an expected viscosity of the compound is determined considering the influence variable by using at least one prediction unit, wherein the prediction unit comprises at least one analysis tool comprising at least one trained model; c) at least one evaluation step, wherein the expected viscosity of the compound is compared to at least one pre-defined and/or pre-determined threshold value, wherein at least one item of output information is generated depending on said comparison; and d) at least one control step, wherein the item of output information is displayed using at least one display device, wherein the output information comprises at least one handling recommendation for at least one setting of the extruder; characterised in that: i) if the at least one expected viscosity of the compound falls within a predefined tolerance range of the threshold value, the handling recommendation comprises information on maintaining the setting of the extruder; and ii) if the at least one expected viscosity of the compound differs from the threshold value by more than the predefined tolerance range, the handling recommendation comprises information on changing the setting of the extruder, wherein the predefined tolerance range is one or both of a relative and an absolute tolerance, wherein the predefined tolerance range is ± 5 %, preferably ± 2 %, and/or ± 3 ml/g, preferably ± 2 ml/g. a) at least one measurement step, wherein at least one influence variable affecting viscosity of the compound is determined by using at least one sensor; b) at least one prediction step, wherein an expected viscosity of the compound is determined considering the influence variable by using at least one prediction unit, wherein the prediction unit comprises at least one analysis tool comprising at least one trained model; c) at least one evaluation step, wherein the expected viscosity of the compound is compared to at least one pre-defined and/or pre-determined threshold value, wherein at least one item of output information is generated depending on said comparison; and d) at least one control step, wherein the item of output information is displayed using at least one display device, wherein the output information comprises at least one handling recommendation for at least one setting of the extruder; i) if the at least one expected viscosity of the compound falls within a predefined tolerance range of the threshold value, the handling recommendation comprises information on maintaining the setting of the extruder; and ii) if the at least one expected viscosity of the compound differs from the threshold value by more than the predefined tolerance range, the handling recommendation comprises information on changing the setting of the extruder, wherein the predefined tolerance range is one or both of a relative and an absolute tolerance, wherein the predefined tolerance range is ± 5 %, preferably ± 2 %, and/or ± 3 ml/g, preferably ± 2 ml/g.