Focusing only on probability - based surveys ( also for the online ones ) , they found overall that the face - to - face ( using show - cards ) and web surveys have quite similar levels of measurement quality , .
The telephone surveys were performing worse .
Focusing only on probability - based surveys ( also for the online ones ) , they found overall that the face - to - face ( using show - cards ) and web surveys have quite similar levels of measurement quality , whereas the telephone surveys were performing worse .