Openness is a quality of a centralized system to allow members and non-members direct influence on its decisions, therefore decentralizing it to some extent for the benefit of both the system and its members.
Influence is defined as data, information, and knowledge shared from individuals who do not make decisions to individuals who make decisions. Openness is a complimentary source of decision relevant information to experts which hold centralized decision power. Example of such systems are ones in which decisions are made by engineers, scientists, managers, product designers, editors, politicians.
Openness informs decisions and minimizes risk of damage caused by insufficient informed. Without openness centralized decision makers can cause damage to some or many members. At the same time openness increases benefits and efficiency of centralized decisions through added information, and it increases member education making acceptance easier.
Openness depends on technologies which enable it. If there are no technologies which directly support it, it is diminished. Reduction of information, like in polls or complex requirements for participation, reduces openness.
Openness also depends on the centralized decision makers ability to use the information: skills, culture, cognitive bandwidth, and management.