Stata help for kapprevi
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help for kapprevi
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Dependence of kappa statistic on true prevalence
kapprevi , r1(#sens #spec) r2(#sens #spec) [ nograph
scatter_options ]
Description
kapprevi provides a graphical representation of the kappa
statistic as a function of the true prevalence of the
characteristic in the population, given specified values of
sensitivity and specificity for two raters. It is an
immediate command, see help immed.
Options
r1(#sens #spec) specifies the sensitivity and specificity of rater 1.
These numbers have to range between 0 and 1.
r2(#sens #spec) specifies the sensitivity and specificity of rater 2.
These numbers have to range between 0 and 1.
nograph suppresses graphical output.
scatter_options are any of the scatter options.
Examples
. kapprevi, r1(0.90 0.95) r2(0.70 .99)
. kapprevi, r1(0.90 0.95) r2(0.90 .95)
. kapprevi, r1(0.70 0.90) r2(0.70 .90) ysize(4) xsize(4)
. kapprevi, r1(0.70 0.90) r2(0.70 .90)
. kapprevi, r1(0.90 0.95) r2(0.70 .99) ysize(4) xsize(4) scheme(vg_blue)
Authors
Nicola Orsini, Division of Nutritional Epidemiology, IMM, Karolinska
Institutet, Sweden
Debora Rizzuto, Division of Geriatric Epidemiology, Department of
Neurotec, Karolinska Institutet, Sweden
Reference
Thompson W.D and Walter S.D. A reappraisal of the kappa coefficient, J
Clin Epidemiol, 1988, Vol.41, n.10, pp.949-959
Support
http://nicolaorsini.altervista.org
nicola.orsini@ki.se
Also see
On-line: help for kappa
Worked examples for kapprevi
Click here to run or save the do-file
. capture net install http://nicolaorsini.altervista.org/stata/kapprevi
.
. which kapprevi
c:\ado\stbplus\k\kapprevi.ado
*! v 1.0.0 N.Orsini & D.Rizzuto 19Oct2005
.
. kapprevi, r1(0.90 0.95) r2(0.70 .99)
Maximum value (kappa, prevalence) = (0.632, 0.294)
. kapprevi, r1(0.90 0.95) r2(0.90 .95)
Maximum value (kappa, prevalence) = (0.729, 0.421)
. kapprevi, r1(0.70 0.90) r2(0.70 .90) ysize(4) xsize(4)
Maximum value (kappa, prevalence) = (0.385, 0.398)
. kapprevi, r1(0.70 0.90) r2(0.70 .90) title(Dependence of kappa on prevalence)
Maximum value (kappa, prevalence) = (0.385, 0.398)
. kapprevi, r1(0.90 0.95) r2(0.70 .99) ysize(4) xsize(4) scheme(vg_blue)
Maximum value (kappa, prevalence) = (0.632, 0.294)