Why you can't trust polls

Actually the title should read why you can't trust legacy media reports about polls. Take for instance CNN's spin on this poll with the alarming headline: CNN Poll: Obama 49%-Romney 47% among likely voters.

Washington (CNN) - With three days to go until the start of the Republican convention, President Barack Obama and GOP challenger Mitt Romney remain deadlocked in the race for the White House, according to a new national survey.

That's the CNN summary of the data. My summary of their summary: Horserace!!! Still a big contest.

But then Josh Marshall reads the fine print in the poll and finds the real story.

This is the first poll that CNN has released with “likely voters” — just like Fox’s most recent poll did. If you look at the number for registered voters it’s a 9 point Obama margin.

What that means is that President Obama has actually gained a bit of ground (obviously within the margin of error) on last week’s eye-popping poll showing him with a 7 point lead over Mitt Romney. But it also shows that turnout and propensity to vote are going to be the whole game going into November.

In other words, CNN cherry picked the data to fit their preferred narrative. They weighted their analysis on the assumption lots of registered voters wouldn't vote, but some guys on a bar stool who say, yeah they're gonna for that bastid Romney just to get rid of the Kenyan Marxist Socialist Usurper before he destroys the gotdam country, are going to actually show up in the voting booth.

Discouraging media fail.

[More posts daily at the Detroit News.]