Trueman - 8:30 pm on Jan 15, 2012 (gmt 0)
@tangor: I assumed that when a user clicks on an ad, the click is evaluated. If the click is valid based on Google's algorithm, then it counts, if not, the click is discarded and we'll never know. Assuming now that another valuation of a click is done after the month has finished, renders the Adsense stats inaccurate. It's more like buying some gas and while paying, they tell you: "Sorry, it costs 11% more, the meter at the gas pump is just an estimate". This behavior is unusual and difficult to explain to Adsense users.
I can live with the fact, but I need to know that to include it in my financial calculations. My eCPM rate might now be lower, for example and I could sell impressions directly for a lower rate.
Could simply be the widget of yesterday is not performing as well today.
Widgets ads might perform better or worse on a given timeframe, but this afaik is tracked in the estimated earnings, because the clicks are counted there.