This is the principle that work should be done at the smallest social unit possible, and the larger units exist to serve the smaller ones. 

For example, the family is the smallest social unit. The family bears primary responsibility for raising and educating children. Thus, the local organization (a public or parochial school) exists to serve the family in that mission.

But some tasks, such as defense, the family cannot do. We really cannot have family tribes armed to the teeth! Thus, defense services are provided at the state or national levels. 

How does it apply in software? Consider the role of small (3-6 person) teams in the larger organization - apply the principle of subsidiarity. For example, all development teams need a bug tracking system. Applying the principle of subsidiarity, is this properly at the small team unit, department unit, or higher organizational unit?

AlanWostenberg, Colorado, 9/24/98
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Is there any leverage to the kind of artifact only a higher level structure can fund and maintain? Networks are an example where there is plenty of leverage in having them funded and maintained at the highest level of an organization. Bug tracking works just fine on little pieces of paper (and test cases and rituals to support them), at the scales I work at. A bigger, better, more complicated system would probably make the process work worse. So, no, bug tracking belongs in the team, with as little technological intervention as possible. 

Is this because most bugs are the manifestation of a lack of communication, and introducing computers almost invariably reduces communication?
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Yes, that is the right question - ''is there any leverage''. Assuming bigger or more technical is necessarily better is what Schumacher (ISBN 0060916303) terms the idolatry of gigantism. 

Do computers necessarily reduce communication? Only when applied to inappropriate scale, like bug tracking in a single small team. It is one scale if you are one pack of six people. Quite another if you grow as we did to thirty sixpacks distributed across multiple international sites! -- AlanWostenberg