Survey vs Historical estimates

in terms of potential biases, what would these two estimates suffer from?

i thought survey estimates would suffer from survivorship bias, since only surviving firms will respond to it, as will historical estimates. but there’s a question in the schweser mocks that says that only historical estimates suffer from survivorship bias.

what are all the other biases that we are supposed to know? backfill bias (can’t remember what it’s meaning is, only remember that hedge funds suffer from it, and fund of funds dont suffer from it as much…i guess its something about funds ‘filling out’ their past financial performance,so they tend to paint a rosy picture)

The bias for survey estimates is selection bias which is also called self-reporting bias. That is, what is reported is better than what is actually experienced.

backfill bias (also called instant history or incubation bias) is related. It’s when funds choose to report only when they have successful returns. Otherwise they don’t report. So historical returns that are backfilled tend to be better than when investors actually put their own money in.

thanks man