A national watchdog group suing the Patrick administration over what it’s calling a broken foster care system is set to file an avalanche of evidence today it says proves the Bay State is rife with neglected and abused kids, overloaded case workers and unchecked officials calling the shots, the Herald has learned.

“There’s no sense of priority in getting results for children,” said Marcia Robinson Lowry, executive director of Children’s Rights, the New York-based child advocacy group that brought the suit against Gov. Deval Patrick, the Department of Children and Families, and the Executive Office of Health and Human Services in April 2010. It’s set to go to trial in January.

Among the filing’s highlights, according to Children’s Rights:

• Massachusetts ranks eighth worst in the country in children abused and neglected while in foster care, according to state data provided to the feds.

• The Bay State consistently shuffles kids between foster homes, some as many as five or more times, making it eighth worst, too, among reporting states on “placement stability.”

• Officials routinely allow children to flounder in state care before they are adopted, putting Massachusetts in the bottom third of reporting states.

• Roughly 15 percent, or one in six children, reunited with their family after being put in foster care ultimately return because of continued abuse or neglec