metap (version 0.7)

sump: Combine p-values using the sum of p method

Description

Combine $p$-values using the sum p method

Usage

sump(p)
"print"(x, ...)

Arguments

p

A vector of $p$-values

x

An object of class ‘sump’

...

Other arguments to be passed through

Value

‘sump’ and ‘metap’, a list with entries

p

The transformed sum of the $p$-values

conservativep

See details

validp

The input vector with illegal values removed

Details

Defined as $$\frac{(\sum p)^k}{k!} - {k - 1 \choose 1}\frac{(\sum p - 1)^k}{k!} + {k - 2 \choose 2}\frac{(\sum p - 2)^k}{k!}$$ where there are $k$ studies and the series continues until the numerator becomes negative.

Some authors use a simpler version $((sum p) ^ k) / k!$ where there are $k$ studies but this can be very conservative when $sum p > 1$. There seems no particular need to use this method but it is returned as the value of conservativep for use in checking published values.

The values of $p$ should be such that $0<=p<=1$ and="" a="" warning="" is="" given="" if="" this="" not="" true.="" an="" error="" possibly="" as="" result="" of="" removing="" them="" fewer="" than="" two="" valid="" $p$="" values="" remain.="" when="" the="" internal="" calculations="" are="" likely="" to="" have="" been="" subject="" numerical="" alternative="" method="" should="" be="" used="" check="" result.<="" p="">

The plot method for class ‘metap’ calls schweder on the valid $p$-values

References

Becker, B J. Combining significance levels. In Cooper, H and Hedges, L V, editors A handbook of research synthesis, chapter 15, pages 215--230. Russell Sage, New York, 1994.

Edgington, E S. An additive method for combining probability values from independent experiments. Journal of Psychology, 80:351-363, 1972.

See Also

See also schweder

Examples

data(edgington)
sump(edgington) # p = 0.097