"However the low numbers suggests that a "forum " like yesterday day only attracts very engaged voters prepared to talk directly to candidates, whereas a speech format asks less of the attendee.
"They sit and listen and don't need to be proactive."
Mr Cooper said the candidates were happy with the format of Saturday's meeting, where they were seated around the hall to be available to talk with people.
The byelection was called when newly elected councillor Jayne Golightly resigned in September after learning she was ineligible because she was not a New Zealand citizen.
There are 13 candidates for the ward, after an initial 17 being nominated when nominations closed on October 10.
Geoff Abbott, Gavin Benney, Kathryn Darroch, Robert Diamond, Mike Henwood, Joby Hopa, Matt Keene, Chris Leitch, Huhana Lyndon, Kevin Newton, Hayward Norman, Des Wallace and Merv Williams in the running. All were at Saturday's forum except Mr Abbott who put in his apologies.
Then four who have pulled out are Haydn Edmonds, Yvette Poingdestre, Greg Shipton and Vanessa Wilson.
Only Mr Edmonds went through the official process of withdrawing from the byelection in time, which means his name will not appear on the ballot papers. Electoral Services recommends the other three candidates let the public know they are not seeking their votes despite their names still being listed.
Planning for Saturday's forum was done when there were still 16 names on the ballot papers.
"There are 12000 voters in the Denby electorate. I sincerely hope they don't vote without doing some research.
"The candidates and the council deserve better than that," Mr Cooper said.