Over its six-game winning streak Geelong has conceded, on average, 10 goals a game while for the first nine rounds that figure was closer to 15 goals.
That correlation is no surprise to Harley, one of the young leaders of the statistically sixth best defence in the league.
``The backline has been pretty steady for the last three or four years whereas the midfield's had a massive turnover and the forward line has been ever-changing as well,'' Harley said.
``We really enjoy playing together and I think we've developed a pretty good chemistry that's perhaps gone a bit unnoticed throughout the AFL.
``Maybe it's because we're in Geelong and no one really knows too much about us, but we pride ourselves on our performance and care for each other and it's great.''
Much has been made of Geelong's successful move to youth this season.
But the six defenders that kept Collingwood's talent-laden forward line to 15 goals last Saturday are no newcomers.
Captain Ben Graham and veterans Brad Sholl and Brenton Sanderson are the old-heads, but Harley and fellow fifth-year player Matthew Scarlett have emerged as a pair that can play both tall for their size or on a smaller forward.
Harley says the Cats' defence this year is performing collectively rather than playing well individually - something that also applies to Geelong as a whole.
Harley, 24 tomorrow, will this week play his 70th game in succession for the Cats since round 14, 1999.
He played one game for Port Adelaide in 1998, but tired of trying to play under different game plans at Port and SANFL club Norwood, where he would play when overlooked for the Power.
When trade talk came around, he was keen to try his luck at Geelong.
``I don't know if there was ever a place for me in the Port side and I think we're going to have a good side for the next couple of years so I just want to stay here and be a part of that success,'' he said.