[CaptSkip]

"A new independent 500-person poll from Rasmussen...

Why this trend to a smaller and smaller sample size? IIRC, my college statistics class in the '70s taught that the sample size required for a low margin of error is 1100 to 1300 people.

[Coop]

Why this trend to a smaller and smaller sample size?

500-600 is a pretty standard sample size in political polling. The bigger the sample population, the higher the cost and the longer it takes. So often times a slightly higher margin of error is acceptable when weighed against the other two factors.