Updated

The calls come in at a rate of nearly 10,000 a day, to hotlines and law-enforcement offices nationwide, reporting suspicions of child abuse and neglect.

They add up to 3.4 million reports annually — a challenge for state child protection agencies, which must sort out the flimsy reports from the credible, the trivial allegations from the dire. Many states, after an initial review, deem more than half incoming reports to be unworthy of full investigation.

The issue entered the spotlight last week with news that Arizona's Child Protective Services failed to look into 6,000 reports of suspected child maltreatment that had been phoned in to its hotline in recent years.

Other states also have had problems. But in general, experts credit child-protection agencies with diligence and care in sorting reports.