I'm sorry, are we reading the same thing?
"Using a survey created from existing scales, 250 officers were contacted within several departments in Central Florida, of these, 90 officers responded."
Asking cops "do you do crimes" is an interesting methodology, for sure.
How do you think the population wide numbers are gathered?
The core point is that the 40% number is exaggerated BS, if for no other reason than it literally counts "shouting" and "loss of temper". There's no reliable evidence indicating the number for police officers is any different than the general population.
Not merely by asking the perpetrators.
13% of active cops admitting in a survey to domestic violence certainly means the actual number is higher than that.
Which means 12-13% _admitted_ committing physical domestic violence, what has to be a significant undercount.
The 40% study itself even says that the victims reported a 10% rate of physical domestic violence from their partner, but specifically does not indicate who the aggressor is - the officer or their spouse. The study is also 30+ years old at this point. [0]
More recent research from 2009, which imo has a far superior methodology and a larger sample size, says that "over 87 percent of officers reported never having engaged in physical domestic violence in their lifetime" [1]
Other studies [2] [3] report rates between about 2% and 11% for mixtures of one time and recurring domestic violence, which are in line with population averages.
[0] https://babel.hathitrust.org/cgi/pt?id=umn.31951003089863c
[1] http://scholarcommons.usf.edu/etd/1862
[2] http://webapp1.dlib.indiana.edu/virtual_disk_library/index.c...
[3] https://digitalcommons.law.umaryland.edu/cgi/viewcontent.cgi...