When Open Space is not the answer
Open Space works well for complex challenges with many stakeholders and no ready-made answer. For a share of the requests I get, it is the wrong choice. This page describes which ones.
Harrison Owen asked the question himself
In Open Space Technology: A User's Guide, Owen devotes his second chapter to what he calls the most important question: should you do it at all? His answer is that Open Space is not appropriate everywhere. He names four conditions under which the form works best: high complexity, many different perspectives, conflict that exists or threatens, and urgency.
If one of those four is missing, there is usually a better instrument.
Four situations where I advise against it
The outcome is already decided. If the decision has been made and the gathering exists to build support for it, Open Space is risky. Participants notice within an hour that their agenda does not count, and you lose more trust than a straightforward presentation would have cost.
The group is too small. Below fifteen to twenty participants there are too few people for parallel sessions. A dialogue format works better. For a conversation that needs depth I use Conversation Café, sometimes as a run-up to an Open Space later in the programme.
Knowledge has to be transferred. If the group needs to learn something already known outside the room, Open Space is a detour. A good speaker with room for questions is faster.
A decision has to be made. Open Space produces a harvest: everything participants wrote down themselves. If a choice has to be made by the end of the day, you need a decision method alongside it. Consent-based decision-making works well here, or structured prioritisation.
The critique from within
The most useful critique of Open Space comes from facilitators rather than sceptics. Johannes Schartau wrote The Tyranny of Open Space in 2017. He calls it explicitly not a call to stop using the form, but a call to stop overusing it.
His diagnosis: the urge to tear down structures often leads to them not being replaced by anything. In that void the same problems reappear, now with a layer of smugness over them.
He describes patterns every facilitator recognises. The session host getting their rejected conference proposal in anyway. The session where novices advise each other badly. The consultant who hijacks the room. The quiet session where everyone waits for someone else's wisdom.
His central point matters most. Open Space solves a problem at the level of the whole group and offers nothing for what happens inside the individual sessions. That is a real gap. It is why I always discuss in preparation how the conversations themselves will take shape. For microstructure inside sessions I use Liberating Structures, a separate craft with its own site.
What I do instead
If Open Space does not fit, I say so during the exploratory conversation, usually within the first fifteen minutes. Often another facilitation format does fit, and you can reach me for that via workshopfacilitation.eu. Sometimes the answer is that you do not need a facilitator but a decision.