Last week Google announced they have updated the numbers on some of the reports to round at a higher level. Google said, "Instead of showing numbers rounded to two or three digits, the numbers will now be shown with one or two significant digits. For example, instead of Webmaster Tools showing you 246,000 impressions, it will now show 250,000 impressions, which is a nicer representation for a better, less confusing experience."
So I reported at Search Engine Land that the reports were now less accurate because of the rounding. Of course my title was very leading and technically, the reports were not exactly accurate from the beginning. As I explained, they were only 90% accurate anyway, so rounding doesn't make them any less accurate when they have that 90% give anyway. New Googler, Pierre Far explained this in a comment:
Numbers in Webmaster Tools are representations of what we call buckets (the +/-10% ranges you refer to in (see above ). These representations work a lot like bucket names and all weíre doing here is changing the names slightly to remove some confusion. There isnít really a gain nor loss of in transparency nor accuracy because although the names changed slightly, they still represent the same buckets. The goal now and previously is to make webmasters aware of significant changes to long-term trends and not bog them down in minute fluctuations.
Had we changed the sizes of buckets by making them bigger, then yes, you can make an argument about loss of accuracy, but we didnít change the bucket sizes.
Hope this clarifies things a bit more.
But still, it seems to the lay person that the rounding makes it less accurate.
In any event, a WebmasterWorld is debating the accuracy of the reports within Google Webmaster Tools. Some are saying they are completely wrong, some are saying it is off by 10x and some are saying it is pretty accurate.
I wanted to poll our audience and see how accurate you think it is. No numbers, just answer the poll below:
Forum discussion at WebmasterWorld.