"Central to the issue of
iron triangles is the assumption that bureaucratic agencies, as players in the political game, seek to create and consolidate their own power base.
The idea is that an agency's power is determined by its constituency, not by its consumers In economics, consumers are individuals or households that "consume" goods and services generated within the economy. Since this includes just about everyone, the term is a political term as much as an economic term when it is used in everyday speech.
Typically when businesspeople and economists talk of "consumers" they are talking about person-as-consumer, an aggregated commodity item with little individuality other than that expressed in the buy/not buy decision. However there is a trend in marketing to individualize the concept. Instead of generating broad demographic and psychographic profiles of market segments, marketers are engaging in personalized marketing, permission marketing, and mass customization.
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For these purposes, constituency may be defined as a group of politically active members sharing a common interest or goal; consumers are the expected recipients of goods or services provided by government bureaucracies (often identified in an agency's written goals or mission statement)."
http://encyclopedia.thefreedictionary.com/Iron%20triangle