Park (2006) reports a union difference of 5% for all employees, greater for women (12%) than for men (2%), but also finds that non-standardised workers excluded from the trade union of enterprises are paid less in trade union enterprises. Unions are also associated with an increase in the employment of non-standard workers, indicating that companies are replacing them with more expensive union work. On the basis of a survey of enterprises conducted in 1991, Kleiner and Yee (1997) estimated the impact of trade unions and works councils, considered “effective” by managers and workers, on the results of non-solicitation. They found less fluctuation, similar productivity and lower job satisfaction among workers in unionized settings. On the other hand, they found that works councils were in favour of productivity and satisfaction. Trade unions and works councils appear to have influenced decisions on dismissal and reduction. Collective agreements are always concluded at company level between management and company unions (with very rare exceptions such as the seafarers` union). .