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Comment by arn | Hacker News Reader

I hate how people cite Compete.com traffic graphs as "fact". Fact #1 is not a fact at all.

Reference point: http://siteanalytics.compete.com/macrumors.com/ (estimated traffic, graph goes down) vs http://www.quantcast.com/macrumors.com (measured traffic, graph goes up)

I also like how he cites Compete's numbers for TechCrunch (1 million uniques), but doesn't use Compete's numbers for his own site PostPost. Compete says PostPost gets 18k uniques/month yet he cites 100K uniques. Why not compare apples to apples?

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It's terribly inaccurate, based on my experience. For the Feb 2011 (most recent available stat they have), they were wrong by -314%. They should make the fact that their service is inaccurate obvious; otherwise, they're misleading many people.

Their data points are from 2 million people. In the U.S. alone, there are 230 million+ interet users: http://www.google.com/publicdata?ds=wb-wdi&met=it_net_us...

I only took basic stats courses in college, but I know enough to know that's nowhere close to a big enough sample size to be statistically significant.

> I only took basic stats courses in college, but I know enough to know that's nowhere close to a big enough sample size to be statistically significant.

Just like you can't get a statistically significant result about the 300 million Americans by phoning a few hundred people.

"I only took basic stats courses in college, but I know enough to know that's nowhere close to a big enough sample size to be statistically significant."

I am not a statistician, but I'm pretty sure you're wrong about that.

The real problem isn't the small sample size (2 million is really large), it's probably that they're not representative.

If that were a random sample you'd be completely wrong -- that's more than enough to get extremely accurate numbers.

What's more likely is that compete is based on a panel [1] [2], and the members of that panel tend not to include the type of people that read tech sites.

[1] http://techcrunch.com/2010/02/25/compete-data/

[2] http://www.quora.com/Where-does-Compete-get-its-data-from

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