People might be confident enough to ask a question or interact well in a conference. Does it mean that they are confident at work? In my opinion it would be hard for someone to assess the confidence level of an individaul from what we see outside-the appearance, communications or a smiling face.
The following article appeared on the Globe provides a more appreciable answer to the question.
Two women walk into a boardroom for a meeting. One sails in with her shoulders back, takes a seat at the centre of the table, and speaks up. Another quickly sinks into a line of chairs against the wall, and spends the meeting silently hunched over her notebook. Who is more confident?
While confidence may be hard to articulate, we know it when we see it. And those whose stock-in-trade is to help build it say the stakes could not be higher.