We don’t know. It isn’t really possible, but Google will still tell us conflicting information like this sometimes. At the time this article is being written (9/19/11) it seems to happen in < 1 in 1000 keywords.

If you were to go check with Google via a tool like the Traffic Estimator, you should be able to see the same conflicting information. It seems as though Google want to promise more clicks than is plausible on this keyword.

Can’t reproduce the discrepancy with Google? Try increasing your max CPC bid. While the CPC bid won’t affect any search volume data it may affect other stats. Still can’t reproduce the data issue? Well then the next time we refresh our own data the discrepancy should disappear from our side as well. Google is a moving target and our stats are updated monthly, so we may be reflecting some dated results.

In conclusion, take heart! We’re very aware of all of the oddities in Google’s pricing/search volume information and have been honing our ability to estimate real statistics on domains for years. We take all of these things into account for a domain’s stats. But when it comes to a term’s stats, we can’t do too much more than reflect what Google tells us.