The other day when I looked at the NAA’s NadBASE site, and glanced at the spreadsheet charting how newspaper Web sites extend local audience reach, I was curious — what newspapers are doing the best at extending reach?

I’m no statistician — didn’t even take the course in college — so maybe my methodology is full of holes, but I just dumped the table into a spreadsheet and calculated the differential of the percentage of total reach minus newspaper penetration for the given DMA.

Total reach is measured by Scarborough Research through surveys and is based on a “visit within the past 30 days” metric, which I think is of dubious value, but it is how these things are being measured. Scarborough claims this is unduplicated, extended, local reach.

If my methodology or logic is flawed, I invite somebody else to take a stab at establishing the same comparison.

If my calculations are right, the average newspaper.com extends the reach of the newspaper by a differential of 3.3 points.

Here are the Top 10 performers, based on this math:

At the bottom of the pile are mostly suburban newspapers in fragmented markets, so maybe expecting stronger performances isn’t realistic, but for what it’s worth, here’s the bottom 10.

Again, FWIW, and I welcome comments, corrections, feedback on the comparisons, but it seems to me that if one paper reaches 55 percent of the market in print, and 58 percent combined, and other is 18 and 20 and another 45 and 53, there is some comparative value in just subtracting one number from the other and seeing who has the better differential. And if it does, maybe we should be trying to learn all we can from the sites that are beating industry averages by wide margins.