Socio-technical analysis is made at three levels - the primary work system; the whole organization; and macrosocial phenomena. - Eric Trist

The work organization of the new seam was, to us, a novel phenomenon consisting of relatively autonomous groups interchanging roles and shifts and regulating their affairs with a minimum of supervision. Cooperation between task groups was everywhere in evidence, personal commitment obvious, absenteeism low, accidents infrequent, productivity high. The contrast was large between the atmosphere and arrangements on these faces and those in the conventional areas of the pit, where the negative features characteristic of the industry were glaringly apparent. The men told us that in order to adapt with best advantage to the technical conditions in the new seam, they had evolved a form of work organization based on practices common in the unmechanized days when small groups, who took responsibility for the entire cycle, had worked autonomously.

# Primary work systems. These are the systems which carry out the set of' activities involved in an identifiable and bounded subsystem of a whole organization - such as a line department or a service unit...

This paper introduces a concept of organizational ecology. This refers to the organizational field created by a number of organizations, whose interrelations compose a system at the level of the field as a whole. The overall field becomes the object of inquiry, not the single organization as related to its organization-set. The emergence of organizational ecology from earlier organization theory is traced and illustrated from empirical studies. Its relevance to the task of institution-building, in a world in which the environment has become exceedingly complex and more interdependent, is argued.