Knowing and Navigating Decision Rules

“You’re making decisions by consensus, but are you collaborating?” by opensourceway is licensed under CC BY-SA 2.0.
by Lorea Mendiguren ’23

Decision rules are a crucial part of multi-party negotiation. Whether it’s a shift in policies in the workplace, the passing of legislation in Congress, or the adoption of a World Trade Organization ruling, the process for determining how a decision is made has a major impact on the way that negotiations proceed. As frequent participants in decision-making settings, it is important to understand the impact decision rules have on voting parties and how to approach them. This piece will introduce the most common decision rules—majority, chair decides, unanimity, and consensus —as well as some variations and steps for navigating them as a participant.

Majority Rule

Simple majority rule means that an agreement is validated when the majority (over 50%) of voting parties support it. Under majority rule, parties with minority perspectives are generally at a disadvantage in the decision-making process because their inclusion in the final agreement depends on the decisions of majority-agreeing parties.1 A primary concern is that parties with minority opinions will be excluded from the agreement, or included in an agreement with terms that are dominantly dictated by the majority coalition.2

Majority Rule
Strengths Vulnerabilities
  • Straightforward to understand and administer
  • Generally seen as reducing discussion time compared to unanimity or consensus; can be advantageous where time is limited.
  • Potential for changing initial distributions of power where there is a dominant powerful player because low-power members have opportunities to form coalitions.3
  • More likely than unanimity or consensus to facilitate emergence of task conflict, which is found to help foster high-quality decisions.4
  • Increases the number of affected participants who can exercise self-determination in collective decisions.5
  • Allows for fallibility or presence of spoilers without decision-making necessarily being hampered (as it may under consensus or unanimity).6

  • Little incentive to consult with minority participants,7 which may result in exclusion of their opinions from the agreement.8 This can lead to:
    • Lower-quality outcomes due to absent information
    • Lack of support from such participants
    • Implementation challenges
  • Can result in instability of decision-making the rule is used by a narrow majority with recurring voting relationships (for example, in Congressional bicameral passing).




Variations of the Majority Rule:

One common variation of majority rule is a qualified majority or supermajority rule, which exceeds an absolute majority by requiring more than half of the group (for example, a two-thirds majority) to support a decision. Supermajority rule may mitigate some of simple majority rule’s risks because it requires greater interaction with minority participants to garner sufficient support and lessens instability when voting participants are frequently in flux. 9 However, decision-making under supermajority rule may be hampered where there are powerful minority coalitions (consider, for example, the use of the filibuster in U.S. Congress).10 Another variation is a relative majority or plurality rule (as used in the U.S. Supreme Court), whereby the most participants vote for an option, but it does not have to be over 50% of the group. Plurality rule facilitates quicker decision-making, but it also allows for wins to occur with small amounts of support and can encourage lateral voting against (rather than for) outcomes.

An opposite deviation from majority rule worth noting is submajority rule, which allows a predefined numerical minority to authorize a decision.11 Examples include the Supreme Court’s ‘Rule of Four’12 or the United Nations’ resolution permitting an emergency special session to be called if requested by the Security Council on the vote of any seven (out of fifteen) members. Under submajority rule, minorities can apply accountability and transparency measures on majorities.13

Chair Decides (Autocratic Model)

Under this rule, decisionmaking power rests with a single decision-maker. Examples include a judge, sovereign, or Chair selecting an outcome.

Autocratic Model
Strengths Vulnerabilities
  • May result in absence of valuable input and innovation from non-decision-making stakeholders.
  • If not widely supported, could result in implementation issues.
  • Decision-making processes are often hidden from public view.
  • Reduces the number of affected participants who can exercise self-determination in collective decisions.14

A variation of the chair decides rule is board decides, whereby decision-making power is still placed within a small autocratic authority, but more than one decision-maker is involved. This rule defines the set of decision-makers, but there may be other rules at play within it (for example, a board might make decisions under majority or consensus).

Unanimity Rule and Consensus Rule

Unanimity and consensus rules are often lumped together due to their similarity in outcomes and negotiation approaches, but their processes are distinct. Unanimity requires that all decision-making participants affirmatively agree to a decision.15 Consensus, on the other hand, is typically understood to mean an absence of disagreement, or that no participants actively object.

A variation of the traditional consensus rule is reverse consensus, which is used to overcome a default decision. The most well-known example of reverse consensus is in the World Trade Organization’s Dispute Settlement Body proceedings, whereby a Panel Report is adopted unless there is a consensus against adoption.

Unanimity & Consensus
Strengths Vulnerabilities
  • Distributions of power may not change much as both powerful and less powerful players have veto votes.17
  • May be less likely than majority rule to facilitate emergence of task conflict, which helps foster high-quality decisions.18
  • More time is spent on negotiation.19
  • Overlooks fallibility, human error, or the potential of spoilers that can hamper decision-making.20

Strategies for Navigating Decision Rules

Three strategies are key for engaging participants and stakeholders: analyzing interests, building coalitions, and involving opposers. The ideal implementation of these strategies will vary depending on what decision rule is at play.

Analyze Interests — and consider breadth versus depth

Whatever the decision rule, it is crucial to determine what interests are at play. Under majority, unanimity, or consensus rule, begin with breadth over depth. Understanding group positions, common concerns, and potential points of sway across the group will help maximize efficiency in identifying and addressing key issues (rather than focusing on interests that are not widely-held). This allows negotiators to identify like-minded parties they may be able to form coalitions with, determine what parties are on the fence, and isolate blocks for opposers.

Since the autocratic model has fewer decision-makers, depth is more imperative. Digging beyond the decision-maker(s)’s positions and getting at core interests opens space for value creation. To do this, it is helpful to identify influential parties close to the decision-maker(s) who offer valuable insight to their interests and other environmental factors that may influence their decision.

Build Coalitions — find negotiation “influencers”

When parties share compatible interests, they can form coalitions to push for a decision collectively. Decision rules influence how decision-making power is distributed between individuals and coalitions. Working strategically within a decision rule can empower coalitions to dominate or strongly influence the final allocation of resources.21

In majority rule, a coalition’s size reflects its voting power. Negotiators should first aim to identify parties with common interests, articulate points of agreement with those parties, and form blocs. In the interest of growing the coalition, parties should foster partnership with ‘maybes’—especially ones with influence that can bring others with them. Consider what interests are unmet for fence-sitters, how communication can be persuasively tailored, and how value might be created within existing coalition focus points or by expanding the issues considered.

The impact of coalitions in the autocratic model, unanimity rule, and consensus rule lies in their influence (rather than their voting power). Negotiators under an autocratic model are focused on winning over the decision-maker rather than other parties—but coalition-building can still play an important role. Having the final say rarely means that an autocratic decision-maker doesn’t care about stakeholder interests or, at least about the impact of having disgruntled stakeholders. Forming a coalition with opposing stakeholders to demonstrate this risk to the decision’s support and implementation can be an influential tactic under an autocratic model. Under unanimity and consensus rules, on the other hand, the priority is managing holdouts to avoid a veto. As a result, coalition-building can be precocious: negotiators should avoid power imbalances that may turn off opposers with minority perspectives, and instead prioritize fostering a collaborative environment where interests, perspectives, and ideas are shared openly. Thus, though less powerful or minority parties could see value in creating coalitions to bring issues to the table, more powerful parties should avoid dominating agendas through blocs and instead prioritize building trust and equity.

Engage with Opposers — build relationships and value

Engaging with as many participants’ voices as possible, including those of opposers, is beneficial. First, decision-making is substantively improved when more participants contribute information and perspectives. Having a widely-supported decision among decision-makers and stakeholders also fosters buy-in and efficient implementation. Finally, negotiators should strive to maintain positive relationships with other parties, particularly where relationships are ongoing.

Unanimity and consensus rules inherently require communicating with opposing parties. This communication should be aimed at understanding interests and mitigating points of concern (rather than merely persuading). Ensuring opposing voices feel heard can help reduce negative feelings associated with the decision that may arise from core relational concerns22 being ignored. It also allows negotiators to gather valuable information that may help create value and reduce opposition.

Majority rule and the autocratic model are susceptible to blocking opposing voices because their support may not be necessary to come to a decision. Still, both typically rely on implementation by oppositional parties or non-decision-makers. Decision-makers under both models should thus actively converse with opposers and assess their concerns in earnest—both to build goodwill and to, where possible, mitigate points of tension. Non-decision-makers under an autocratic model can also strategically engage with oppositional parties. If a negotiator is oppositional, they can build coalitions with other opposers as described above. If a negotiator is supportive, they can engage with opposing interests to craft solutions and strategies that the decision-maker may find valuable — essentially doing some of the leg-work and helping to close the gap in getting to “yes.”


We make countless decisions within decision rule structures every day. Understanding the impacts of decision rules and how to navigate relationships within them is the first step in ensuring that you are leveraging the rule to your advantage rather than working against it.


[1] See Adrian Vermeule, Absolute Majority Rules, 37 B.J. Pol. S. 643, 645 (2007).
[2] Id.
[3] Gideon Falk, An Empirical Study Measuring Conflict in Problem-Solving Groups Which are Assigned Different Decision Rules, 35 Human Relations 1123, 1124-1126 (1982).
[4] Falk, supra note 3, at 1134.
[5] Rebecca L. Brown, The Logic of Majority Rule, 9 Journal of Constitutional Law 23, 31 (2006).
[6] Schwartzberg supra note 7 at 7.
[7] Melissa Schwartzberg, Counting the Many: The Origins and Limits of Supermajority Rule (2013).
[8] Femke S. Ten Velden, Bianca Beersma, & Carsten K. W. De Dreu, Majority and Minority Influence in Group Negotiation: The Moderating Effects of Social Motivation & Decision Rules, 92 J. of Applied Psych. 259, 259 (2007).
[9] Id. at 6.
[10] Id. at 7.
[11] Adrian Vermeule, Submajority Rules: Forcing Accountability upon Majorities, 13 The Journal of Political Philosophy 74, 74–76 (2005).
[12] Id. at 75.
[13] Id. at 75.
[14] Brown, supra note 4, at 31.
[15] Ten Velden, Beersma, & Dreu, supra note 8, at 259.
[16] Ten Velden, Beersma, & Dreu, supra note 5, at 259.
[17] Falk, supra note 3, at 1126.
[18] Id. at 1134.
[19] Gideon Falk, Unanimity Versus Majority Rule in Problem-Solving Groups: A Challenge to the Superiority of Unanimity, 12 Small Group Behavior 379, (1981).
[20] Schwartzberg supra note 7, at 7.
[21] Jeffrey T. Polzer, Elizabeth A. Mannix, Margaret A. Neale, Interest Alignment and Coalitions in Multiparty Negotiation, 41 Academy of Management Journal 42, 44 (1998).
[22] Daniel Shapiro & Roger Fisher, Beyond Reason: Using Emotions as You Negotiate (2005).


Lorea Mendiguren ’23 is a J.D. candidate at Harvard Law School, and was a Spring 2022 student in the Dispute Systems Design Clinic, where she worked on a project involving multi-party negotiation that aims to reopen St. Paul’s College, a historically black college in rural Virginia. Over the Winter term, she greatly enjoyed her position as a Teaching Fellow in the Negotiation Workshop. Lorea’s legal focus is in global regulatory law and diplomacy. Her studies combine interdisciplinary interests in dispute resolution, civil rights protections, comparative law, and legal history.  Her columns this semester will draw on all of these areas of expertise and will turn a negotiation lens on geopolitical events, international trade, the challenges of group dynamics, and more. Outside of her dispute resolution interests, Lorea serves as the Editor-in-Chief of the Harvard International Law Journal. She is also the Conference Chair for La Alianza, HLS’s Latinx affinity community. Prior to starting at HLS, Lorea graduated from the University of Southern California summa cum laude, where she completed an Honors Thesis exploring literary, theological, and pseudo-legal representations of women in romantic literature of the Middle Ages.
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