That voice of the other end of the phone sounds sincere enough, and the name of the organization certainly inspires empathy. But as a yearlong investigation by the Tampa Bay Times and The Center for Investigative Reporting has found, that charity trolling for your money could well be shamefully short-changing the causes it purports to help.

The news organizations identified almost 6,000 charities that pay for-profit companies to raise their donations. The 50 worst of them, the report finds, have paid their solicitors nearly $1 billion over the past 10 years -- money that donors undoubtedly assumed would be going directly to cancer research, disabled veterans and the like.

Five of them are in Southern California: Hope Cancer Fund, National Narcotic Officers Associations Coalition, Find the Children, Shiloh International Ministries and Association for Firefighters and Paramedics.

The inglorious 50 devote less than 4 percent of donations raised to direct cash aid, the report found. Some, like the West Covina-based Narcotic Officers group, gave exactly zero percent.

How does one differentiate the responsible charites from the dubious sound-alike groups? Ask specific questions: How long has the charity been around? Exactly where do our donations go? What percentage? Get familiar with charity-rating organizations like Charity Navigator and GuideStar USA. And read the report at . It's got the full list of the 50 worst charities and more tips on how to root out the bad ones from legitimate ones that deserve our ongoing support.