No.
Google Traffic Estimator accuracy seems to have been lost in the sands of time, updates and shinier tools. It is woefully underestimating traffic for top search trends in the UK. Consider the recent Swine Flu outbreak (which the British media is making into an I am Legend epidemic). On Google Insights for Search, you can clearly see two distinct uplifts in traffic volume; one when it broke in April, and another since we started seeing more and more rates of infection and media attention:
Now take a look at Google Traffic Estimator's traffic predictions for the term "swine flu" - 0 clicks a day? £1 per day? Never mind the mathematics of dividing by zero, but how often is this updated? How can Google suggest using the traffic estimator with results as inaccurate as these:
When projecting costs and clicks for your internal stakeholders or for clients, make a point of querying the accuracy of the Traffic Estimator. Use your own judgement and search engine marketing know-how - remember that it's perhaps in Google's best interests to underestimate so that you will have to feed more money to keep up a seemingly impossibly great traffic level. Never rely on a sole source of information when building a campaign from scratch, or even expanding it.
If there wasn't a case for research before - here's your clear justification to invest in a proper keyword prediction tool or extra resource for human research.
