The Robins have taken 13 points from nine games since Sean O'Driscoll was appointed as head coach in January but they currently find themselves bottom of the Championship, two points adrift of safety.
With 11 games of the season remaining, Anderson believes that the team needs to pick up at least 15 more points to guarantee survival.
"My personal opinion is that it is going to take a minimum 50 points to stay up this year," he told the Bristol Evening Post.
"It's usually a bit less than that and last year it slumped a bit because there were a few teams that really struggled. There have been a lot of unexpected results and all the teams around us have been winning.
"When that happens, it raises the bar for everyone and we are going to need at least 50 points if we are going to be safe."
Bristol host Brighton & Hove Albion in the Championship on Tuesday evening.