We describe three corrections that should be applied to the observed relative incidence of nearby stars hosting giant planets .
These are diffusion in the stellar atmosphere , use of the [ Ref ] index in place of [ Fe/H ] for metallicity , and correction for local sampling with the W velocity .
We have applied these corrections to a subset of the SPOCS exoplanet survey with uniform giant planet detectability .
Fitting the binned data to a power law of the form , \alpha 10 ^ { \beta [ Fe / H ] } , we derived \alpha = 0.022 \pm 0.007 and \beta = 3.0 \pm 0.5 ; this value of \beta is 50 % larger than the value determined by Fischer & Valenti ( 6 ) .
While the statistical significance of this difference is marginal , given the small number statistics , these corrections should be included in future analyses that include larger samples .