A reader asked what the margin of error is on the Top 20 Online Current Events & Global News Destinations from Nielsen//NetRatings. Here’s the company’s not-so-satisfactory answer:
“The concept of ‘margin of error’ is a statistical concept that has nothing to do with data being correct or wrong,” says NetRatings Senior Data Analyst Corinna Chang. “The term that better describes this concept is ‘confidence interval.’ The confidence interval is a statistical law that doesn’t depend on the quality of a survey, the way a survey is put in place, nor the methodology used. The confidence interval depends on three factors: 1) sample size , 2) the “certainty factor”, and 3) the penetration of the Website.
“A confidence interval would have to be calculated for each individual site. This information is not readily available but is calculated upon request by clients.”
