Schneier on Security

Try this:

"Intrafamily murderers are especially likely to have engaged in far more previous violent crimes than show up in their arrest records. But because these attacks were on spouses or other family members, they will rarely have resulted in an arrest. So domestic murderers' official records tend not to show their full prior violence, but only their adult arrests for attacking people outside their families. Most family murders are preceded by a long history of assaults."
[http://www.ncjrs.gov/App/Publications/abstract.aspx?ID=127648]

More:
"Intrafamily murderers are especially likely to have engaged in far more
previous violent crime than show up in their arrest records. But because
these were attacks on spouses and/or other family members, they will
rarely have resulted in an arrest.{169} So domestic murderers' official
records tend not to show their full prior violence, but only their adult
arrests for attacking people outside their families. Therefore only about
"seventy to seventy- five percent of domestic homicide offenders have been
previously arrested and about half previously convicted."{170} As to how
many crimes they perpetrate within the family, even in a relatively short
space of time, "review of police records in Detroit and Kansas City" shows
that in

90% of the cases of domestic homicide, police had responded at least
once to a disturbance call at the home during the two year period prior to
the fatal incident, and in over half (54%) of the cases, they had been
called five or more times.{171}

A leading authority on domestic homicide notes: "The day-to- day reality
is that most family murders are preceded by a long history of
assaults...." Studies (including those just cited) "indicate that
intrafamily homicide is typically just one episode in a long standing
syndrome of violence."{172}"
[http://homepage.usask.ca/~sta575/cdn-firearms/Digests/600-699/v01n667]

Why the difference? I can easily see the possibility that cultural differences result in significant differences as to when and how often police are called, or how often police actually create a written record when then are called (which would be indistinguishable to after-the-fact data mining studies.)

I also get quite cautious when I see qualifications of the sort included in the study you cite:

"It found that nearly three-quarters of spousal homicide offenders had no prior contact with police for spousal violence."

How is the study defining "spousal violence"? How many police contacts did the researchers not count, because they didn't consider it to be "spousal violence"?

Another Canadian study:

"The study indicated that factors associated with firearm-related domestic homicide include: a history of violent disputes (however, in the majority of these disputes the police do not have previous knowledge); a history of substance abuse; drunkenness; an existing criminal record; separation or pending separation; and, employment and financial problems."
[http://www.cfc-cafc.gc.ca/pol-leg/res-eval/publications/reports/1990-95/summaries/dom_sum_e.asp]

That the police are sometimes unaware of the pattern of violence in these cases does not mean that the victims are not.

I'll say it again - if your domestic partner has not assaulted you in the past, the odds that he or she will do so in the future is nil.