The trade unions' attitude in principle tended to favour money compensation for hazards and stress. This wage policy and efficiency policy could only be realised as long as the economy was prospering and companies were ready to make material concessions by granting higher wages and special bonus schemes. On the side of the trade unions these developments – together with the trend towards economic recession which has rendered high wage demands as compensation for deteriorating working conditions impossible – have led to the inclusion of effort bargaining into their collective bargaining policy. The demand for elimination of restrictive working conditions has recurred at several trade union meetings and conferences. The trade unions only turned away "from the idea of compensation for a lack of job-satisfaction" after the strikes in the metal working industry of Nordwuerttemberg/Nordbaden in 1973. For the trade union conception of eliminating restrictive working conditions in industrial production is mainly based on experience drawn from mechanised production processes.