A method is provided for assessment of quality of an adhesively-bonded lap joint, wherein the joint includes a first metal plate, a second metal plate and an adhesive therebetween. The method includes sending ultrasonic waves normally to the surface of a sample outside of the joint where the sample has a first sample metal plate with the same properties as does the first metal plate at an assessment point of the joint. Reflected waves from the sample joint as a reference waveform are recorded. Wideband ultrasonic waves are sent normally to the surface of the joint at the assessment point. Reflected waves of the ultrasonic waves from the joint are recorded. A waveform of the reflected waves from the joint and reference waveform are analyzed to determine an informative parameter. The informative parameter is compared with a threshold value to assess quality of the joint.