re: #108 Charles

In the New Zealand case, the temperature data was adjusted for a very simple and very obvious reason — the station was moved to a higher altitude, where temperature readings are naturally lower. There’s nothing unusual or strange about that kind of adjustment — in fact, if you don’t do the adjustment the data will not be accurate.

I’m not arguing, either for or against, any particular circumstance. Just pointing out that data filtering is common, and is also not always as straightforward as tossing out the outliers.

Even when tossing outliers, statistical analysis is required to determine what, exactly, constitutes an outliers, and why.