I have been using adwords for years as an advertiser and lately my reporting has shown some weird stats for weeks. I know my niche very well and one of the keyword phrases I have ads for is not typically a "high" volume keyword. Suddenly in the last week or 2 , the keyword phrase has exploded to a huge number of impressions and clicks that dont really make sense. Keyword is 'home refinancing rates' and its impressions in the last 7 days were over 3000 ! Normally a popular mortgage related keyword phrase in one week will get around 100 - 500 impressions and thats if its really popular and set to a broad match. Also, google keyword tools shows this phrase on a local result getting only 150 impressions per month??? So how can I get 3000 impressions in 7 days??? Im totally confused as to whats going on and why google adwords shows such high impressions and clicks while keyword tools shows that this phrase should be getting way lower performance? My problem is that this phrase is now eating up my budget and im not sure if the clicks are real or not. Just doesnt look right. Can I trust google reporting for adwords and for their keyword tool stats as well?
I've had a similar thing happen to me once so I looked at the search queries that were leading people to click on my ads and found that an algorithm change had calsed my keyword to start getting matched against an irrelevant keyword. I just looked at the Google Keyword tool and "Home refinancing rates" is projected to get 8,100 queries per month in the USA so 3K in one week doesn't sound crazy high if you have it on broad match. You can always trust there reporting, but you can't always trust your ability to interpret the reporting. Often you need to talk to an account rep if something looks fishy.
Maybe others with the same keyword have ran out of advertising credits. this would make your keyword impressions soar. Just a thought since I am no expert on google.
Lots of things can come into play for an increase in impressions: Competitors for the keyword not showing because of budget having been reached or simply dropped out. With less ad inventory, you show on first page more often. Algorithmic changes that trigger ads more often, particularly on broad matches. That's why broad matches are to be used very carefully. This sounds like it's the source of your problem. There is also actual increases in searches for whatever reason.