Avoiding Bias from the Survivor Effect
http://www.useit.com/alertbox/20020624_survivoreffect.html

Nielsen, Jakob
Alertbox
2002

Abstract:

Only a few of the survey sites we analyzed in 2000 are still around. We can safely assume that the surviving sites are not a random sample of the original group, but rather that significant differences exist between the sites that made it and those that died. Survival might be due partly to luck, but it is mainly a result of good management and an understanding of Internet fundamentals. Thus, the surviving sites are likely to be disproportionately clued-in about what it takes to run an online business.