There is, however, one fundamental problem: There is no comprehensive sampling frame for the internet, no way to draw a national sample for which virtually everyone has a chance of being selected. The ...

Methodologically, in all or nearly all cases, ABC News requires a probability-based sample, with high levels of coverage of a credible sampling frame ... See a weighting table from our April ...

Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...