In April 2006, IBC published a lengthy response to their critics entitled "Speculation is no substitute: a defence of Iraq Body Count".[25] In their reply, IBC argues that their critics have several key facts wrong. IBC argues that while their estimate is likely to be below the full toll, their critics' errors have led the critics to exaggerate the likely extent of such an undercount. Finally, IBC argues, the available evidence does not support their critics' claims of a pro-US bias infecting the IBC database.