That’s the actual study,
She found that approximately 40 percent of the officers surveyed reported that they had behaved violently toward their spouse and/or children in the last six months and that 10 percent of spouses reported having been physically abused by their partner. However, as there was no operational definition of abuse employed, it is not possible to determine from this work the severity of the abuse or what proportion of the officers may have been referring to verbal as opposed to physical abuse, nor is it possible on the basis of this study to determine the rates of violence relative to other normative samples.
“Although the limited sample size and narrow range of variables investigated limit the con- clusions that can be drawn”
That’s the first line of the concluding sentence in the study.