Calculation of Keyness

[Xiaoxiao Kong]

Hi,

I was wondering how keyness in AntConc is calculated - is it as is shown here: http://ucrel.lancs.ac.uk/llwizard.html ? As far as I understand this doesn't account for negative keyness (since the formula cannot generate negative values). How then is negative keyness calculated in AntConc?

I'm trying to compare the keyness (positive and negative) of two sets of corpus data (C1 and C2), and I'm doing it in terms of how they compare to C1+C2 (what you put in as the reference corpus). I've realised that some of the negative keywords of C1 show up in the positive keyness of C2, which is what you would assume, but the absolute values of the keyness strength in these two cases are different. I'm thinking that it might be due to the different corpus sizes of C1 and C2, but since I don't know how exactly are positive and negative keyness calculated I can't say for sure. Can someone please explain this?

Cheers,

Xiaoxiao

[Laurence Anthony]

Hi 

I was wondering how keyness in AntConc is calculated - is it as is shown here: http://ucrel.lancs.ac.uk/llwizard.html ? 

Yes. This is what AntConc uses.

 

As far as I understand this doesn't account for negative keyness (since the formula cannot generate negative values). How then is negative keyness calculated in AntConc?

If the frequency in the target corpus is less than in the reference corpus, it is marked as a 'negative' keyword.

I hope that helps.

Laurence.

[Xiaoxiao Kong]

Thank you very much Laurence, could you specify the formula used to calculate negative keyness (because I think it's different from the calculation of positive keyness)?

Xiaoxiao

[Laurence Anthony]

Just add,

If freq (tar) < freq (ref), keyness = keyness * -1

Laurence.

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Laurence ANTHONY, Ph.D.
Professor of Applied Linguistics
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Waseda University
3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
E-mail: antho...@gmail.com
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