More than 350 researchers at Infogroup are dedicated to building, verifying and updating their databases by scrutinizing information from hundreds of public sources. Infogroup combines multiple data sources to deliver the most robust and comprehensive database available, which includes 4300+ Yellow and White Page directories, hundreds of county-level public sources, and lifestyle data providers with over 1.5 billion consumer indicators. Infogroup also makes over 24 million phone calls per year to verify business data and collect additional information.