System analysis is part of the behaviouralist movement in political science  and as a reaction to traditional approach .In this search of theory building some scholars saw the potential of General System Theory  by Ludwig Von Bertanalffy.Participatory support - voting , political discussion etc
Paying attention to gvt communication like ads , ceremonies,symbols etc
Easton's Output  : Policies and decisions 

Taxation and economic  policies
Regulation of human behaviour
Distribution of resources ; provide opportunities
Symbolic outputs , communication of policy intent.He selected political system as a unit of analysis and concentrated on intra system behaviour .He holds that all political systems are both open and adaptive.He studied the nature  of exchanges and transactions that takes place in a closed circuit but is made because of the demands from the society or  environment.Because of the supports from the environment they become authoritative.250px-easton-system_of_political-life

Easton's input   consists of demands and support .Obedience of laws,rules.