<unk>  happens when survival<unk>  appears longer because diagnosis was done earlier (for instance, by screening), irrespective of whether the patient lived longer.<unk> <unk>  is duration of<unk>  between detection of a disease (by screening or based on a new experimental criteria) and its usual clinical presentation and diagnosis (based on traditional criteria). For instance, it is the<unk>  between early detection by screening and the<unk>  in which diagnosis would have been made clinically (without screening). It is an important factor when evaluating the effectiveness of a specific test.<unk>  occurs if testing increases the perceived survival<unk>  without affecting the course of the disease.
Lead time bias
Publication bias
Information bias 
Recall bias
Age bias 
Length time bias
Funding bias
Ceiling effect 