Does an auctioneer affect the final selling figure on the day of auction?

My opinion is yes.

A good auctioneer is identified not when there are 17 people registered to bid on a “screamer” but the true ability is displayed on a property where there may only be 1 or 2 people registered and no one wants to go first.  A good auctioneer has the innate ability to sense the mood and rhythm of what pace should be used to allow “momentum bidding. ” A good auctioneer will have the ability to truly connect with bidders and engage them during a time where these bidders have most likely put on their defence shield. A good auctioneer has to prevent the audience from getting restless. He does this with an endless supply of positive information about the area and specifically about the property.

Conversely a bad auctioneer can end up being your worse nightmare. They are boring and repetitive. It creates a restless environment where people begin to fidget. At their worse they can be insulting to buyers. 

The choice of auctioneer is important. Absolutely!  Because if you get the bad auctioneer you are un-doing 4-5 weeks of marketing and work in one minute.