Table 1.

Measurement system.

Parameter	Relationship in Figure 5	What is measured?	Measure unit
Knife time	C	Duration: starting point–first incision, end point–end of the procedure.	Minutes, seconds
Ratio and severity level of complications	E, F	Number of complications / overall number of performed procedures and severity of the complications, if any.	Ratio coefficient and a grade in the Clavien-Dindo classification scheme for surgical complications [24]
Score in rating scale (surgical education)	B	Scores in the predefined scale to measure the progress of education.	Rating score
Duration (surgical education)	B	Duration required to reach the same level in the rating scale.	Hours
Accuracy of mentoring	A	1) Number of guidance misinterpretations (possibly leading to errors), 2) Number of requests to clarify the guidance, 3) Total time spent on guidance during the procedure, and 4) Number of interruptions of the flow of the procedure for mentoring.	Combined score