Parliamentary procedure is the rules of democracy. When a group of people meets for the purpose of a common goal, such as a meeting, decisions are made in the best interest of the organization. Parliamentary law is based on considering the rights of the majority, minority, individual members, and absentees.
From National Association of Parliamentarians website: Parliamentary procedure defines how groups of people, no matter how formal or informal, can most effectively meet and make decisions in a fair, consistent manner- and make good of everyone’s time. While parliamentary procedure cannot guarantee that every member of the organization is pleased with the outcome of a decision, it aims to ensure that every member is satisfied by the manner in which the decision was made and that the organization makes decisions efficiently but with consideration for every member’s opinion.
Group using parliamentary procedure include but are not limited to: legislatures, city and county councils, school boards, community/homeowners’ associations, boards, charitable organizations, churches, clubs, unions, fraternal and professional organizations.
A deliberative assembly is a group meeting to determine action to be taken in the name of the entire group, after free and complete discussion. Each member is free to make decisions based on their best judgment and each vote is weighed the same for each member. Rules governing absentee members/votes may be established. Types of assemblies include: legislative bodies, boards, conventions, mass meetings or an assembly of an organized society.