Google watchers are anxiously awaiting the GOOG earnings report due this Thursday. Google shares, trading today at about $477 are off a whopping $270 per share from the 52 week high of $747.

Henry Blodget suggests that Google can show 25% growth but only throug a substantial increase in the price per click, a Google metric that won’t be clear until the Thursday report.

This 25% growth estimate obviously assumes that Google has seen a strong increase in price-per-click: If it hasn’t, and the Comscore data is accurate, US revenue will miss by a mile and Google’s overall revenue will come in well below consensus. Thursday’s earnings report will be interesting.

Click revenues are very dynamic making it hard to predict the effect on revenues of the changes at Google which are a funciton of of total paid clicks, which are up but very modestly over last years, and the revenue *per click*, which can vary with season, market, user interface, and other factors. Google has been seeking better quality control for pay per click advertisements which appears to have increased the revenue per click but also was a key factor in the huge decrease in the growth rate of total clicks.

As Bloget notes, Thursday’s earnings report will be very interesting.

Disclosure: No position in GOOG