Industrial relations is a multidisciplinary field that studies the employment relationship. Industrial relations is increasingly being called employment relations or employee relations because of the importance of non-industrial employment relationships; this move is sometimes seen as further broadening of the human resource management trend. Indeed, some authors now define human resource management as synonymous with employee relations. Other authors see employee relations as dealing only with non-unionized workers, whereas labor relations is seen as dealing with unionized workers. Industrial relations studies examine various employment situations, not just ones with a unionized workforce. However, to a large degree, most scholars regard trade unionism, collective bargaining and labor-management relations, and the national labor policy and labor law within which they are embedded, as the core subjects of the field.