Yes, it works quite well to get a sense of the room. The advantage of humming is that people can change the volume to match their level of agreement with the qu

Yes, it works quite well to get a sense of the room. The advantage of humming is that people can change the volume to match their level of agreement with the question being asked. If they strongly agree with the question, they can hum very loudly. If they only weakly support it, they can hum quietly. The chairs of thesession can then get an audible sense of the level of agreement (or not). Often in the sessions I've been in, there may be two hums taken - one for those in support of a question, and one for those opposed. Often there can be a clear distinction - but sometimes the results can be inconclusive if both sides seem to have equal volume. (But that, too, is helpful to the chairs as they can get a sense that the people in the room are divided.)