• Title/Summary/Keyword: paradox of kappa

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Weighted Hω and New Paradox of κ (가중 합치도 Hω와 κ의 새로운 역설)

  • Kwon, Na-Young;Kim, Jin-Gon;Park, Yong-Gyu
    • The Korean Journal of Applied Statistics
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    • v.22 no.5
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    • pp.1073-1084
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    • 2009
  • For ordinal categorical $R{\times}R$ tables, a weighted measure of association, $H_{\omega}$, was proposed and its maximum likelihood estimator and asymptotic variance were drived. We redefined the last paradox of ${\kappa}$ and proved its relation to marginal distributions. We also introduced the new paradox of ${\kappa}$ and summaried the general relationships between ${\kappa}$ and marginal distributions.

A New Measure of Agreement to Resolve the Two Paradoxes of Cohen's Kappa (COHEN의 합치도의 두 가지 역설을 해결하기 위한 새로운 합치도의 제안)

  • Park, Mi-Hee;Park, Yong-Gyu
    • The Korean Journal of Applied Statistics
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    • v.20 no.1
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    • pp.117-132
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    • 2007
  • In a $2\times2$ table showing binary agreement between two raters, it is known that Cohen's $\kappa$, a chance-corrected measure of agreement, has two paradoxes. $\kappa$ is substantially sensitive to raters' classification probabilities(marginal probabilities) and does not satisfy conditions as a chance-corrected measure of agreement. However, $\kappa$ and other established measures have a reasonable and similar value when each marginal distribution is close to 0.5. The objectives of this paper are to present a new measure of agreement, H, which resolves paradoxes of $\kappa$ by adjusting unbalanced marginal distributions and to compare the proposed measure with established measures through some examples.

A simulation study of rater agreement measures (모의 실험을 이용한 여러 합치도들의 비교)

  • Han, Kyung-Do;Park, Yong-Gyu
    • Journal of the Korean Data and Information Science Society
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    • v.23 no.1
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    • pp.25-37
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    • 2012
  • Many statistics, such as Cohen's (1960) ${\kappa}$, Scott's (1955) ${\pi}$, and Park and Park's (2007) H have been proposed as measures of agreement to represent inter-rater reliability. This study compared bias, SE, MSE, and CV of the measures of agreement with nominal and ordinal categories in the balanced marginal distributions, and those with nominal categories in the two paradoxical situations. As a result, in all cases, AC1and Hhad smaller SE and CV.

Inhibitory Effect of Amentoflavone of Selaginella Tamariscina on MMP-9 Expression through NF-${\kappa}$B and AP-1 in Macrophage Raw 264.7 cells

  • Ahn, Byung-Tae;Shin, Sung-Ahn;Kim, Jun-Gi;Park, Won-Hwan
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.21 no.1
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    • pp.243-249
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    • 2007
  • The French paradox has been attributed to the antioxidant properties of flavonoids present in the red wine. Amentoflavone(AF) is a bi-flavonoid compound with anti-fungal and anti-inflammatory activities. We isolated AF from Selaginella tamariscina, and studied its effects on nuclear factor-B(NF-B)-mediated MMP-9 gene expression in RAW264.7 cells. AF blocked the lipopolysaccharide(LPS)-induced expression of MMP-9. Zymographic and immunoblot analyses showed that AF suppressed LPS-induced MMP-9 expression in a dose-dependent manner. To clarify the mechanistic basis for its inhibition of MMP-9 induction, we examined the effect of AF on the transactivation of MMP-9 gene by luciferase reporter activity using -1.59 kb flanking region. AF potently suppressed the reporter gene activity. This inhibition was characterized by down-regulation of MMP-9, which was transcriptionally regulated at NF-B site and activation protein-1 (AP-1) site in the MMP-9 promoter, two important nuclear transcription factors that are involved in MMP-9 expression. These findings indicate the efficacy of AF in inhibiting MMP-9 expression through the transcription factors NF-B and AP-1 on LPS-induced RAW264.7 cells.