Minnesota's county-based child welfare system needs stronger guidance, a legislative audit concluded Tuesday, to eliminate regional disparities over what types of child abuse and neglect cases get investigated.

The audit credited child welfare agencies in Minnesota for making "reasonable and deliberative" decisions about allegations, but suggested several ways to make those decisions more consistent across the state.

In reviewing county child welfare agencies, Legislative Auditor James Nobles's staff found in 2010 that some counties "screened out" none of the abuse and neglect complaints they received, which means they thought they all merited investigation. Others screened out 89 percent of the complaints they received.

The audit encouraged the Legislature to clarify the legal definition of situations that present a "risk of harm" and neglect and merit child welfare involvement. It also encouraged the Department of Human Services to increase its training of intake agencies on how they evaluate and screen child maltreatment allegations.

One facet of the audit was to interview child protection workers across the state and to provide them with 10 fictional allegations to see what determinations they would make.

"Agencies have different approaches to risk of harm and the level of risk sufficient to warrant a child protection response, the report stated. "For example, one vignette that agencies 'screened' involved a small child wandering a block from his home. Some agencies 'screened in' the fictional referral due to the risk of harm to the child. However, other agencies 'screened out' the referral, reasoning that the first-time incident was accidental."