# Thread: how to calculate the significance of an R2 increase (based only on results in paper)

1. ## Re: how to calculate the significance of an R2 increase (based only on results in pap

I prefer this rearrangement of the equation:

where q = number of predictors; k = number of predictors for full model

2. ## Re: how to calculate the significance of an R2 increase (based only on results in pap

Originally Posted by Dragan
Ahem, check your degrees of freedom in the numerator and denominator, Spunky.
i wasn't fully convinced either Dragan because the # of predictors as degrees of freedom just sounds plain wrong to me... nevertheless, this is an exact copy-paste of my (1970s) version of the Cohen et. al. blue book in which i know they worked some sort of transformation (they call this a "computational formula") on the original version but, although it does seem wrong, i cant really change it because i literally just translated what they had on their chapter into LaTeX and placed it here...

3. ## Re: how to calculate the significance of an R2 increase (based only on results in pap

Originally Posted by trinker
Oh yeah I had to calculate that in a linear regression class it's in Cohen Cohen Aiken and West. duh. That's a pretty common formula. Thanks for making me feel like a real ding a ling spunky If my regression prof were to see this he'd not be happy.
MAJOR lol @ trinker for not remembering his regression basics! :P

4. ## Re: how to calculate the significance of an R2 increase (based only on results in pap

Funny...

Cohen, Cohen, Aiken and West 2003 still use the formula spunky gives where as Aiken and West 1991 use the formula where k is the # of predictors of the full regression model.

5. ## Re: how to calculate the significance of an R2 increase (based only on results in pap

Wow. Really noetsi?!?!? Every researcher I've come across has been overly safe and frugal when it's come to data sharing.
What field do you work in? Admitedly the people I worked with had tenure so that might be an issue here.

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