Vigenère, auto-correlation vs Kasiski examination What are the differences between 'Kasiski examination' and 'auto-correlation' ? 

In Cryptool site, they state that autocorrelation analysis is more efficient and clearer than the Friedman or Kasiski test. But, they fail to mention how they achieve this or how they differ from Kasiski.
Kasiski's test only considers repeated sequences of characters, under assumption that the text contains repeated words with distance between them being a multiple of key length.

Autocorrelation analysis simply counts matching characters between shifted ciphertexts. Then you have to identify "maxima", which are shift distances with higher match counts than the others. The assumption here is that the text from the language correlates strongly with itself. This is more general than assuming the existence of long repeated sequences.