I posted these home vs away foul call stats a year or so ago and it seems worthwhile to put them on here again. They only cover the seasons from 2012-13 to 2016-17 as the NBL removed the home/away filter from its players' stats page after 2016/17 and doesn't show fouls on the team stats page (which does have the home/away filter). I'm not keen enough to copy paste foul numbers from 112 box scores for that season. If someone else has those stats, they can post them.
Basically, these stats look at how many more/less fouls each team was called for at home vs away, for the whole season. So they give some sense of the home vs away advantage/disadvantage for each team, from a personal fouls' perspective. The stats alone say NOTHING about the reasons for any difference.
e.g., in 2012/13, Perth's home advantage was -5.1, meaning they were called for 5.1 fewer fouls per game at home than away. That was the biggest home advantage in that season and compared with an NBL average of -1.5.
Apologies for not being able to lay out the table neatly. I don't have the HTML skills and posting may remove the additional spaces I used for formatting.
Team 2012/13 2013/14 2014/15 2015/16 2016/17 2012-17
Adelaide -0.9 -2.6 -1.3 -1.4 -3.4 -1.9
Brisbane - - - - -1.6 -1.6
NZ -0.8 -2.1 -0.4 -1.6 -0.9 -1.1
Sydney -1.8 -1.9 +0.3 -2.4 -0.1 -1.2
Cairns -2.6 +2.3 -3.6 -1.6 -1.5 -1.4
Perth -5.1 -1.6 -1.9 -2.6 +0.1 -2.2
Illawarra +1.3 -0.5 -1.3 -0.4 +1.1 0.0
Melbourne -1.0 -2.5 +0.1 -1.1 -0.6 -1.0
Townsville -1.0 -0.4 -1.1 -0.6 - -0.8
NBL -1.5 -1.2 -1.1 -1.5 -0.9 -1.2
The last column is the summary home advantage for the full 5 year period.
The biggest point I take from this table is pity the Hawks, who had no home court foul advantage at all. The next biggest point is the consistent NBL average across the seasons, of roughly a one foul advantage per game for home teams.
Perth's full year advantage is heavily biased by the 2012/13 season where they had a huge home court advantage relative to the NBL average (nearly three times the NBL average). Only Adelaide's 2016/17 home advantage stands out to a similar extent (nearly four times the NBL average).
While these are historical stats, they do quantify the sort of home advantage you might expect to see over a season in the NBL. Based on the stats given by OP in this thread, Perth's home advantage using this measure is -13.3. There's no doubt that number is way higher than anything in the table above. In particular, it's massively higher than the long term NBL seasonal average.
If we aren't seeing similarly large, atypical home advantages for other teams in this season to date, then there's absolutely something to worry about and the most likely culprit would have to be refereeing. If anyone wants to do test this by checking other teams' 2018/19 home advantages, feel free.
