Please note: this comment is not about the conference I am currently speaking at, and should not be interpreted to reference any particular event. In fact, my hosts here in Bloemfontein have given me free reign in my sessions, with what I feel have been very good results - further endorsement, I feel, of what I say below.
I have always tried to make my talks and sessions learner centered - I come in with an agenda, but I say at the outset, this talk is in your hands, you can direct it wherever you want. Usually they are happy with my agenda, but not always. Yesterday's workshop, for example (audio available soon, I hope) is an example, where we went way off the agenda. But did people learn? Yes - and rather more than they would have learned had I tried to plan and implement the plan.
I have noticed, however, that when I try to turn control over to the learners, there is a tendency for someone else to step in - usually the funder of the event, or more likely, a proxy for that funder - who decides to substitute their own expertise for both my expertise and that of the group, and to implement their own planning, and manage the outcomes. And then, when it fails, to hold the presenter of the workshop accountable, or worse, the audience.
I have in recent years adopted the attitude that people do not acquire instant expertise because they fund something, and that when I am invited to host or participate in a session, I will manage my own participation in my own way. Because a central part of the theory I have developed and that I believe is that this sort of management doesn't work. My seminars, presentations and workshops, therefore, are instantiations of my theory, and not merely descriptions of my theory (and again, I've learned, it's pretty futile to simply describe the theory - people will politely listen and then go back to what they have already done).
The 'outcome', therefore, of one of my talks (or for that matter, any session I attend, because I'm a disruptive influence), if anyone needs a formalized outcome (which I don't recommend, since each individual has their own expectations and needs, which simply cannot be substituted by fiat by authority) is "this method works with this group". The outcome is that we are providing evidence that the method works, we are giving participants experience with the method, and we expect (but cannot promise) that their practices will be changed as a result.
From time to time I do have organizers who state that they would like something more concrete in terms of outcomes, methodologies, processes, assessment, and the like. I gently and politely tell such funders that if they really feel this way, they should fund someone else. This is not said with malice or anything like that, but out of simple recognition of the fact that if a person wants roses, then they should buy roses, and not tulips - and it is unreasonable for me to go in there and pretend that our tulips are roses. They're not. But - I think - they're pretty good tulips. And sceptics can always look at the slides and audio from previous sessions.