Can somebody help me find data for this statistic?

There are two main sources for this statistic. The first is a 1991 hearing before the Select Committee on Children, Youth, and Families in the House of Representatives. The full report, “On the Front Lines: Police Stress and Family Well-Being,” can be found here.

This is from the statement given by Dr. Leanor Boulin Johnson, Associate Professor of Family Studies at Arizona State University, when describing the results of her research:

“Family violence seems to be a problem as well. Some argued that officers who work daily in predominantly negative and sometimes violent environments may unconsciously promote and perpetuate acceptance of violence in their own lives.

We found that 10 percent of the spouses said they were physically abused by their mates at least once during the last six months prior to our survey. Another 10 percent said that their children were physically abused by their mate in the same last six months.

How these figures compare to the national average is unclear. However, regardless of national data, it is disturbing to note that 40 percent of the officers stated that in the last six months prior to the survey they had gotten out of control and behaved violently against their spouse and children.”

The second source is a study published in 1992 in the journal Police Studies entitled “Interspousal aggression in law enforcement families.” The full article is locked behind a paywall, but you can see the first page (including the abstract) here. The abstract also contains the 40% figure (a very slight rounding down of the number found in the actual study, which was 41%). The Fraternal Order of Police found this study important enough that they reprinted it in their own journal later that year.

The reason these studies came to be so widely cited is that both were based on self-reports. Since not all domestic abuse is reported, and since people are likely to downplay the frequency of their own negative behavior, the fact that 40% of officers were willing to admit to committing domestic violence during the past year was considered a big deal. The reason that these numbers continue to be so widely cited is that increasing stigmatization of domestic violence has made it harder to conduct studies like these.

That said, we should bear in mind that (1) these studies are now three decades old, (2) neither was a national study (as Dr. Johnson notes in her testimony), and (3) it is almost impossible to obtain internal data from police departments regarding how often officers are reported and/or investigated for domestic violence (which could potentially give us a broader understanding of the situation and help us fill some gaps in the existing studies).

One last note about methodology: surveys are—or at least can be—a very important part of a study. So while both of these studies used surveys to gather their primary data, neither just stopped there. The data was analyzed using well-tested statistical tools before it was reported.

Thank you @SavoirFaire I understand how hard it is to get accurate data on things like DV and sexual assault, as they are some of the most under-reported crimes out there.

That statement “40%....stated that in the last 6 months prior…they had gotten out of control and behaved violently against their spouse and children” also leads to more questions.

I just questioned it because there are more than 800,000 officers in America. If we keep that number at 800,000 and take 40% of it, that means that 320,000 officers are abusive towards their spouses. That just seems to be really high and a recent study done in 2013 doesn’t really match that.

This article says that “281 officers from 226 LE agencies were arrested for DV” There were 70 officer involved DV in 2005, 116 in 2006, 138 in 2007. The total would be about 16–17% of officers, not 40. But again, they only examined 226 agencies out of 17,985.

This seems to be a very hard thing to try and prove/back up because 1) how under-reported it is and 2) (what you said) it can be hard to get the data from the agencies.

I wonder then how useful it is to use this statistic in arguments. It doesn’t appear to be super well backed up, at least not as of 2020.

But the issues with this could also apply to the stats about rape. That 1 in 6 women have been victims of a successful/attempted attack. It has sources, but you can only go off of what was reported and that won’t be accurate to the true number.

I think another reason why this data may be inaccurate is because if someone goes to their own private therapist and discusses abuse, it’s not going to be reported to any national data bank. Therefore, the information won’t be counted.

@SergeantQueen “I wonder then how useful it is to use this statistic in arguments.”

It’s not useful at all. The studies themselves go out of their way to note that the actual rate of domestic violence in police households is almost certainly different than the numbers they found due to sampling issues, and two studies from 30 years ago about an evolving phenomenon tell us very little about how things are today. This is one of those cases of a number continuing to be cited long after it is relevant.

@jca2 “if someone goes to their own private therapist and discusses abuse, it’s not going to be reported to any national data bank”

That’s why the studies used self-reports instead of official data. But that method has its own issues, so you’re still right that we need to be careful about throwing this number around as if it were definitive.

Well then. I wish people would look into things instead of spreading false info? I’m not taking a high ground here, I’ve said things without fact checking plenty of times but am working to improve on that. It’s more important now than ever.

IMHO you meaning anyone can find data to support most suppositions. While it’s said “statistics don’t lie, liars use statistics”. In the current state of our nation, while contending with multiple p roblems/situations and the certainty that the “news” you hear/read i factual we are living in precsarious times. Uncharted waters, so to speak.