노사 협상력을 나타내는 변수로는 노조(유=1)와 외주비율(외주비/인건비+외주비) 변수를 사용했다.
As variables representing labor-management bargaining power, the variables of the union (yu = 1) and the outsourcing ratio (outsourcing cost/labor cost + outsourcing cost) were used.