What is consensus?

One of the most important insights in my research so far has been to understand that consensus is not the same as unanimity. In a nutshell, unanimity is when everyone agrees and consensus is when no one disagrees. Although this seems like a hair-splittingly small distinction, the difference between the two can be huge in practice.

The French sociologist Philippe Urfalino has done some pioneering work to clarify how unanimity and consensus are different (Urfalino 2007, 2010, 2014). Amongst other things he points out that in order to establish unanimity, it is necessary that everyone forms their individual preference on the matter and expresses it in a vote. Unanimity is reached if everyone votes for the same option. Consensus, in contrast, allows some (or even a majority) to not make up their mind and to simply remain silent. Margaret Gilbert (1987: 194) speaks of allowing something “to stand as the view of [the group]”. Both Urfalino and Gilbert emphasize independently of each other the non-summative nature of consensus (Gilbert’s term is “collective belief”), meaning that collective decisions are not necessarily the sum of individual decisions.

Indeed, I would argue that most of the time we make collective decisions by consensus (i.e. in a non-summative way). This is neither inherently good nor bad, but it is important that we understand what we are doing. In particular, we should recognize that when we decided something by consensus, we cannot assume that each member of the group actually preferred the option that became the decision of the group. It is even possible that some participants (and again: even the majority) are in fact against the decision, but - for whatever reason - remain silent and let it pass.

Having studied decision-making among democratic and often strongly egalitarian activists (Haug 2010), I am aware that some proponents of consensus-decision making will say that if a large numbers (or even just a few) are against the decision but they let it pass anyway instead of vetoing it, then this is not a real consensus decision. However, my impression is that such insisting on a narrow definition of consensus as the only “real” consensus is not very helpful in actually reaching consensus.

Of course, it works fine if everyone shares this narrow definition and understands how it works, but if diverse groups come together and each of them has a different understanding of what consensus is, then it makes more sense to acknowledge that consensus can be practiced in different ways and to see that the commonality between all of them is that they are all constituted by successfully observing the absence of disagreement (Urfalino [2014] speaks of “the rule of non-opposition”): “Is anyone against it?” - “No? Then it’s decided.”

The crux is in how this happens in practice. I suggest that we can distinguish at least four types of consensus in meetings: imposed consensus, acclaimed consensus, basic consensus, and deliberative consensus (Haug 2015). In a nutshell, the difference between these is in how much opportunity there is to voice dissent:

In an imposed consensus, someone (usually the chair) simply claims that consensus has been reached and directly moves on to the next topic or closes the meeting. Participants who feel that this claim to consensus is not accurate will have to be quite articulate in order to make their objections heard while the meeting is already proceeding to a new topic. In fact, they have to disrupt the meeting and demand that the observation of consensus be annulled.

In an acclaimed consensus, there is an explicit “slot” for participants to express their views, but its official purpose is not to express dissent but consent. Participants are asked to confirm that they agree with “the consensus” (e.g. “Does everyone agree?”). The assumption is that, yes, everyone agrees and participants are expected to merely connfirm this assumption (as indicated by the “few muttered ‘agreed’”). A “No” is clearly the less preferred option (implied in the wording of the question and how it is articulated).

In basic consensus, participants are explicitly asked if there is anyone who disagrees. A frequent wording in the meetings I observed was, “Is there anyone who cannot live with this decision?” or simply “anyone against?”, thus providing an explicit slot for dissenters to, “speak now or forever remain silent”, as it were. In this practice, consensus appears as a stretch of silence and by observing this silence as the absence of dissent, participants determine that consensus exists. The silence in this practice affords the voicing of disagreement, making it easy (as compared to imposed and acclaimed consensus) dissenters to raise objections.

Deliberative consensus (the term is inspired by Beatty and Moore’s (notion of “deliberative acceptance”) not only gives participants the opportunity to express dissent, but actively encourages that dissent is articulated in order to make sure that no one is silenced. For example, the facilitator may take up previously contested issues and ask the dissenters whether their concerns have meanwhile been sufficiently addressed, or if there are tentative signs of disagreement such as “rumours” from the coffee break or someone frowning, these might be taken up by asking something like “Are you sure we’ve reached consensus? Peter, you look unhappy.” In contrast to the other forms of consensus, deliberative consensus encourages dissent – not in the sense that dissent is welcomed, but in that there is a particular concern for dissenters being silenced. The encouragement of objections serves to counteract institutional pressures by creating an atmosphere of appreciation for each individual’s point of view.

Although deliberative consensus seems to come close to unanimity, it is still fundamentally different from unanimity because even when dissent is encouraged, participants are still free to not form a preference on the matter at all and there may still be some who disagree but who don’t want to stop the group from going ahead, be it because the decision is not important to them or because they see no point in arguing any further, or for whatever other reasons they may have.

I think that this is one of the main reasons why consensus decision-making is so popular, even in meetings where by-laws suggest that decisions are made by voting. Having to make up your mind about every single damn issue that’s on the agenda can be very demanding. Consensus allows people to let others whom they trust and/or deem competent basically make the decision for them.

Hence, despite its reputation, consensus is not necessarily an egalitarian form of collective decision-making because “incorporates a general acceptance of inequality in individual contributions to collective decision-making. The general equality of participation to the process coexists with a recognition of the legitimacy of unequal influence of individuals, depending on social status or expertise” (Urfalino 2014: 339). Rather than being inherently democratic in a liberal sense, it seems that the benefits of consensus are mainly in it’s capacity for “deciding without dividing” (Urfalino 2014: 333).


Gilbert, Margaret (1987): Modelling collective belief. In: Synthese, Vol. 73, No. 1. pp. 185–204. DOI: 10.1007/BF00485446

Haug, Christoph (2010): Discursive Decision-making in Meetings of the Global Justice Movements: Cultures and Practices. Doctoral thesis. Freie Universität Berlin, Fachbereich Politik- und Sozialwissenschaften. Berlin.

Haug, Christoph (2015): What is consensus and how is it achieved in meetings? Four practices of consensus decision-making. In: Joseph A. Allen, Nale Lehmann-Willenbrock & Steven G. Rogelberg (Eds.): The Cambridge Handbook of Meeting Science. New York: Cambridge Univ. Press. pp. 556–584. DOI: 10.1017/CBO9781107589735.024

Moore, Alfred & O’Doherty, Kieran (2014): Deliberative Voting: Clarifying Consent in a Consensus Process. In: Journal of Political Philosophy, Vol. 22, No. 3. pp. 302–319. DOI: 10.1111/jopp.12028

Urfalino, Philippe (2007): La décision par consensus apparent: Nature et propriétés. In: Revue européenne des sciences sociales, Vol. 45, No. 1. pp. 47–70. DOI: 10.4000/ress.86

Urfalino, Philippe (2010): Deciding as bringing deliberation to a close. In: Social Science Information, Vol. 49, No. 1. pp. 111–140. DOI: 10.1177/0539018409354812

Urfalino, Philippe (2014): The Rule of Non-Opposition: Opening Up Decision-Making by Consensus. In: Journal of Political Philosophy, Vol. 22, No. 3. pp. 320–341. DOI: 10.1111/jopp.12037


But on a more serious note, the fascinating thing is that in actual practice meetings work the other way around: At meeting 1, no clear consensus can be reached on question X (but something like a hegemonic position emerges). At a subsequent meeting 2, someone claims that meeting 1 agreed on the answer to question and nobody objects.

In other words, what a single meeting cannot achieve, a series of meetings can pretend to have achieved.

In my thesis I called this “post-hoc decision”: people just declare retrospectively that a decision was made and nobody objects because nobody was there or remembers sufficiently well or because the dissenting minority is now absent or perhaps because nobody could be bothered re-opening the debate.

or because those with power are saying that is what happened…

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I hesitate to use power to explain something. To me, power is something to be explained. So rather than saying: So if I observe that people pretend that a decision has been made at the last meeting even though I did not see that decision happening, rather than saying “It became a decision because those with power said so”, I’d rather investigate what prevented that assertion from being challenged (and by consequence gave power to those who said so).

One thing that can be confusing in this definition concerns the operations of formal approving groups where they have an explicit definition for consensus that is achieved through multiple rounds of voting. When I worked with standards-setting organizations, I always started by reading the bylaws to see how they formally define and achieve consensus. It was fascinating to see how incredibly complex the process became in highly contentious but not critical settings, such as high-tech standards (INCITS, W3C, others) where those who’s preferences come through make more money. Those groups went multiple rounds and had simple majority definitions for consensus.
By contrast, groups working on safety standards had very simple rules; near unanimity. I believe NSF defined consensus at like 95% agreement before they’d approve a standard.
These groups really make it clear how important and effective a strict deliberative process can be because they are essentially all fierce competitors working together. It’s not a fast process, but it works in a way that makes international commerce possible. I’m always saddened to see how many social good organizations eschew these processes as “too heavy”, only to then fail in achieving anything of note.

The term consensus is obviously used in a number of ways and there is nothing wrong with an organization defining it as a formal procedure that involves voting. Obviously, my (or Urfallino’s) definition above will not help anyone understand what is going on in the meetings of that organization (unless they, ignore their by-laws and operate more informally, which does happen, as you know). The purpose of pointing out that consensus does not involve voting and is therefore different from unanimity (which requires voting) is to help make sense of those situations where there are no bylaws and meeting participants (or observers) are perhaps misunderstanding what they are actually doing, i.e. they might be using consensus but they say they made a unanimous decision.

More generally speaking, I think the main critique of my definition of consensus would be that it focuses on the final moment of establishing consensus while there is a lived tradition of consensus as a (potentially) long process aimed at maximizing inclusion and acceptance of the decision. People who advocate for this kind of decision making will probably find my definition too broad (after all, their aim is precisely to avoid what I call “imposed consensus”). But my definition is not a normative one. I am trying to understand why people speak of consensus to describe rather different practices. And for that purpose, I find it incredibly enlightening to say that they all mean that no one opposed the decision. The difference is in how that situation of non-opposition was achieved.

I’d be curious to read that definition(s) of consensus that you encountered in the bylaws of various organizations. Do you have them at hand?

These are available online, and there are hundreds of them. Here are few that illustrate the idea. Tip: I recommend searching on the word “consensus” to quickly get an overview. I used to teach these documents to developers and used that same technique to point out that the word “comment” doesn’t have a single obvious definition.

ANSI essential Requirements
This is the US national organization for accrediting standards. These requirements are an approachable distillation of the International requirements. Every accredited US standards group then drafts more specific policies that incorporate these essentials.

These folks develop technology standards for programming languages and codecs. The stakeholders involved are often direct competitors with a vested interest in how the standard comes out, as certain clauses will better suit one vendor’s technology than another’s. These policies are more complicated than most, and have far more provisions in place to deal with the reality that these guys regularly get subpoenas challenging their activities.

By contrast, this organization deals with community health and safety, which felt to me like it was way more important to get right. Their policies are much simpler, but also more stringent.

You’ll see here that “consensus” is something these groups achieve through multiple rounds of voting, some of which happens in meetings and some of which does not.

A personal observation: this all feels very heavy and arcane when you first start looking at it, but as I got deeper, it became one of the triggers for my interest in meetings. I realized that by following these processes, these companies worked together to shape how international commerce, safety, and communications evolve, despite the fact that they were explicitly hostile to each other’s interests.
Later, I was asked to consult with an organization that wasn’t handling community input well and was getting repeatedly hammered for lack of transparency. I recommended they adopt a light version of these processes, which make representation and the consideration of input very clear. They decided that all this was “too formal” for them. They have since spent multiple millions on audits, fancy transparency dashboards, and other attempts to prove their fair dealings, with no discernable improvement in their reputation.
Uptight and clear IS uncomfortably formal and sometimes slow, but it works. Deliberative processes have their place.

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