In the agency's review, "one thing that became apparent was that many children had serious medical issues," Evans said. Nearly 1,200 children had physical health problems, 332 had developmental issues, and 1,052 had behavioral health issues.

Given the numbers, some say the new hires may not be enough.

"It's an excellent idea, but four nurses for this number of children is too few," said Dan Taylor, a pediatrician at St. Christopher's Hospital for Children, where many abused children are taken.

"Unfortunately, DHS is one of the only eyes we have into these kids' homes," said Taylor, adding that some infants and children he treats may go years between appointments.

The agency recognizes that problem, Evans said, and will not depend only on nurses. DHS will require workers who see children to conduct safety inspections during each home visit and promptly report when a child misses doctor's appointments.

He also wants to respond more quickly to children who are younger than 2.

"These are the children who are most at risk and where we have the most deaths."

Evans said he wants workers - contractors - to see children under 2 years old at least weekly. "We will put eyes on kids," he said.

Communication between contractors in the field and DHS caseworkers in the office is critical because DHS staffers do not normally provide direct services. They oversee the contractors who do.

Evans said the agency is scrutinizing contractors more carefully. It has ended new cases for four contractors who provide services to children in their own homes, terminated one foster-care contract, and stopped sending new cases to another.

In the Kelly death last summer, DHS had hired a service provider who it now says was falsifying paperwork to indicate home visits that were never made. To prevent this in the future, DHS is hiring five additional staff to oversee contractors.

"We need to work better with providers to make sure they are doing a better job," said Evans.

He said the agency needs to develop the capability to conduct yearly evaluations of contractors and perform random audits. Currently, reviews are done once every two years.

Evans said DHS is upgrading training and computer systems, continuing changes started under previous commissioners.

One system, for example, will allow supervisors to oversee and track every decision a caseworker makes.

So what will it all cost? Evans said that it's too early to tell, but that the agency has most of the money it needs, and that the state has committed to help. One key question is how both the city and state will make sure the changes continue under the next mayor.

"My intention is to get so much momentum behind these reforms that they will keep moving forward," Evans said.

Read continuing coverage of the city child-welfare agency at http://go.philly.com/dhs

Contact staff writer John Sullivan at 215-854-2473 or johnsullivan@phillynews.com.