I have always believed most tools that shows how much a keyword is searched per month hasn't been very accurate. Then when Google released their Keyword tool, I thought they would be very accurate since it's from Google after all. But is this really the case? I mean to me it seems awfully wrong. For example I have a site that ranks number one for keywords that according to Google has over 30 000 searches per month, and when looking at Analytics, that keyword has sent me about 300-400 visits per month. I have another keyword that has over 110 000 searches per month, and my site ranks number 3 for that, still when looking in Analytics I get around 400-500 visits per month for that keyword. These are just a few examples. I am aware that your description and title can have a big impact, but let's face it, are you number 1 for a keyword that is searched 30 000 times per month according to their tool, you should get more than 400-500 visits. What do you guys think? Am i 100% wrong here? Have you researched and found another keyword tool that are actually much more accurate? I believe a perfect Keyword tool is invaluable.
None are really accurate. Take Google as you mentioned. Their results (as far as I am aware) are just based on Google.com seraches, so for the likes of me using Google.co.uk the results are (relatively) pretty meaningless. Now I could be wrong anout that, but last time I checked, this was the case (Someone correct me and post a proving link if that's the case). What this means to me using Google.co.uk and UK searches and searches is the data is well out of wack. I know of no toll that accurately does things in real time. I find everything somewhat lacking even the awesome Awstats in cPanel's that I find very interesting at times (though obviously a slightly different subject).
They are all just estimates. Ur best bet is to use multiple KW Research tools so you can cross check against each other. If you really want to figure out a solid figure one method is to use ur adwords account. Pick you kewword and put a ridiculously high bid so you will be on the number one position, and put the description completely unrelated so noone will click ur ad. After 24 hours you will see how many impressions that kw got. Disclaimer: Do not use ur main adwords account for this as ur CTR will be 0% and QS will take a nosedive.