this just occured to me: yeah, the keyword suggestion tool is really nice at DP, but the data isn't coming from google. so my question is, assuming you're in the same position (calculate the estimates at something really really high- you should get a position of 1.1), is the changes in estimated clicks per day ONLY based on the change in traffic? or do you think they average in a "normal" CTR for that term as well? if they don't, then you could really use the estimates to guage how many searches something gets IN GOOGLE- not overall edit: in all my tests, it certainly seems to at the very least, correlate with the keyword suggestion data- but I'm guessing/hoping it's more accurate for google specifically?
Yep... I think it's based on Google searches. Although exact numbers or multipliers I have no idea about.
I've done some experimenting with Google Adwords and the traffic estimation vs ad position and CPC. I think Google bases the estimation on the clicks the ads are getting at that position, so some lower positions get more "traffic" than higher ones. You would have to know the CTR % for specific ads and keywords to get a better reading on total searches. (Remember if someone makes a really catchy ad and it gets a higher than average click through ratio this can throw you off.) Also you have to remember the estimation is only for one average position not across the whole board, so you really have to take quite a few things into account. Oh and not forgetting some of that traffic will come from "publisher content" (Adsense sites) rather than searches as well. Try using Overture's keyword suggestion tool and multiply it by about 1.5 to get a rough idea of what google is working through for searches.