@80 Interesting link. I followed from the link you provided to the source document, here:
On pages 22 and 23 it talks about the difference between the methodology of the National Family Violence Survey, and the methodologies of the National Violence Against Women survey and the National Criminal Victimization Survey. (NFVS shows gender parity in committing DV, the others show men as majority perpetrators.)
The difference is, the NFVS asks about both what acts you *committed*, and what acts you were a victim of. The others only ask about victimization. In the NFVS, if a woman says she hit her male partner, that counts as a male victim. But in the other two, a male victim only gets counted if the man himself says he is a victim.
I.e., the evidence for gender parity comes from *women themselves* saying yes, I hit/kicked/threw something at my partner. It stands to reason that men are unlikely to admit being victimized by a woman (or even to perceive the act as an assault). I'd compare this to sexual assault: it is widely accepted that women are reluctant to report sexual assault, due to socialization/shame/etc. The same socialization may lead men to under-report physical assaults by women.
2 other points: regarding murders, while it does seem that more men kill their female partners than vice versa, the discrepancy isn't as extreme as this makes it sound. In 2010, 241 men and 1095 women were killed by intimate partners. That means of the total 1336 people killed by intimate partners, 18% were men. Stating it as a percentage of total murders, rather than looking at the percentage of domestic murders, magnifies the difference, because men are much more likely to be murdered overall.
The number of women who kill their partners may also be understated, because cases where women hire killers, or get boyfriends or some local teenage boys to do the deed may be counted as multiple-perpetrator homicides rather than intimate partner homicides.
Finally, as for the CTS not capturing motives, such as control or coercion, here's a report indicating that motives like anger, control, and jealousy are significant factors in women's use of intimate partner violence: http://www.ncbi.nlm.nih.gov/pmc/articles…
E.g., one study found that "38% of women who used IPV stated that they had threatened to use violence to make their partners do the things they wanted him to do."