Assay validation using the concordance correlation coefficient jstor. It was first proposed by fisher4 and is defined by assuming that results of the diagnostic tests follow a oneway anova model with a random effect for subject. Estimating felledtree stump volumes in the pacific northwest. Introduction in health care practice, clinical measurements serve as a ba sis for diagnostic, prognostic, and therapeutic evaluations. Overall concordance correlation coefficient for evaluating. This concordance correlation coefficient evaluates the degree to which pairs fall reproducible if it is performed by welltrained personnel symbol m, but not. Morgan results and discussion groundlevel stump diameter estimates.
As technology continues to advance, new methodsinstruments for diagnostic, prognostic, and therapeutic evaluations be. Package cccrm july 8, 2015 title concordance correlation coef. This random effect accounts for the repeated measures for each subject. An understanding of lins concordance correlation coefficient is obtained if the line of best fit to the data comparing two methods is shown in a scatterplot when the results from one method are plotted. Pdf on jul 1, 2008, joe matsuoka and others published intraclass and. Pdf a concordance correlation coefficient to evaluate. Let us first consider that both x and y are univariate. A tolerance interval approach for assessment of agreement in method comparison studies with repeated measurements. The manytomany mapping between the concordance correlation. Evaluation of reproducibility for paired functional data. Ipn tools for testretest reliability analysis file. Interoperator reproducibility was assessed using only the first data set no duplicate.
Computer programs for the concordance correlation coefficient. The wensel and olson equation provided superior estimates of groundlevel diameters with the highest concordance correlation coefficient of 0. Concordance correlation coefficient 0fold crossvalidation. Interoperator reproducibility was assessed using only the first data set. Agreement for interrater measurements was also analyzed using blandaltman plots 35,36,37. Lins concordance correlation coefficient introduction this procedure calculates lins concordance correlation coefficient from a set of bivariate data. Methods for evaluating the agreement between diagnostic tests. Barnhart department of biostatistics, the rollins school of public health of emory university, 1518 clifton road ne, atlanta, georgia. Lins concordance correlation coefficient may be calculated as an index of reliability. A note on the concordance correlation coefficient thomas. The statistical properties of this estimate can be satisfactorily evaluated using an inverse hyperbolic tangent transformation. Use of the concordance correlation coefficient as a mea sure of reproducibility has gained popularity in practice since its introduction by lin 1989, biometrics. Lins concordance correlation coefficient lin, 1989, as well as the limitsofagreement procedure bland and altman, 1986.
Details for each program and procedure are discussed in their individual panels. Logtransformed absolute percentage difference was also used to evaluate the concordance correlation coefficient, a measure of agreement encompassing both bias and variability. This statistic quantifies the agreement between these two measures of the same variable e. Pdf the concordance correlation coefficient is one of the most common. Shear wave elasticity by tracing total nodule showed high. To assess the reproducibility of elasticity measurement, intra and interrater agreements were evaluated using the intraclass correlation coefficient icc. The scaling into the range from 1 to 1 may have been motivated by the fact that the pearson correlation coefficient also falls within the range. Barnhart department of biostatistics, the rollins school of public health of emory university, 1518 clifton road ne, atlanta, georgia 30322, u. Article pdf available in computer methods and programs in. Pdf the concordance correlation coefficient is one of the most common approaches used to assess agreement among different observers or instruments. This expression, first introduced by, is known as the concordance correlation coefficient, abbreviated as ccc hereafter. Cccs were calculated adjusting for leftright, spinal location and for trial 1trial 2 differences. Modeling concordance correlation via gee to evaluate.
The macro has been produced in both sas and r, and a detailed presentation of the macro input and output for the sas program is included. A spatial concordance correlation coefficient with an application to image analysis. Lin 1989, biometrics 45, 255268 objected to the use of the intraclass correlation coefficient as a way to evaluate the reproducibility of measurements between two trials of an assay or instrunent and developed an alternative called the concordance correlation coefficient. The withinsubject coefficient of variation and intraclass correlation coefficient are commonly used to assess the reliability or reproducibility of intervalscale measurements. Comparison of reproducibility or reliability of measurement devices or methods on the same set of subjects comes down to comparison of dependent reliability or reproducibility parameters. Intraexaminer and interexaminer reproducibility of. Lins concordance correlation coefficient ccc is the concordance between a new test or measurement y and a gold standard test or measurement x. The concordance correlation coefficient ccc is based on the distance in the plane of each pair of data to the 45 degree line through the origin and was used to quantify the reproducibility of multiple readings made by the same examiner. Ik 2000 a note on the concordance correlation coefficient. This index is the correlation between the two readings that fall on the 450 line through the origin. Summary a new reproducibility index is developed and studied. Suppose that x 1, y 1, x n, y n are independent and identically distributed paired observations from x, y. Alternative estimators for evaluating agreement and reproducibility based on the. The basic functions include the matlab implementation of icc intraclass correlation coefficient, ccc corcordance correlation coefficient and kendalls w or kcc kendalls coefficient of concordance.
When directionality as well as magnitude was part of the relationship between outcome and predictor as for differences in uptake time, difference in logsuv max. We examined agreement between breast pathologists across europe scoring stils. Lins concordance correlation coefficient ccc is the concordance between a new test or. Lins concordance correlation coefficient correlation coefficient with small sample tanggal 20 february 2009, teh lusi menanyakan bagaimana mengihung korelasi dengan sampel kecil n definitions and terms. Let x and y denote scores from two raters or measurements from two instruments. Lin, a concordance correlation coefficient to evaluate reproducibility. The concordance correlation coefficient is one of the most common approaches used to assess agreement among different observers or instruments when the outcome of interest is a continuous variable. Intraclass correlation program page provides a two ways analysis of variance, then the intraclass correlation coefficient agreement program page provides two programs, the bland altman plot.
Testretest reproducibility of 18ffdg petct uptake in. Biometrics 57, 931940 september 2001 modeling concordance correlation via gee to evaluate reproducibility huiman x. Recently, lin 2000 issued an erratum reporting a number of typographical errors in his seminal 1989 paper. A new reproducibility index, called the concordance correlation coefficient, has been proposed lin. In health care practice, clinical measurements serve as a ba.
For continuous data, the concordance correlation coefficient ccc. Ik 1989 a concordance correlation coefficient to evaluate reproducibility. This index is the correlation between the two readings that fall on the 45 degree line through the origin. Pdf a concordance correlation coefficient to evaluate reproducibility.
The ccc macro is presented for computation of the concordance correlation coefficient ccc, a common measure of reproducibility. The concordance correlation coefficient symbolized by mean of. Lins method is applicable for studies evaluating two raterstwo methods without replications. Comprehensive experiments that evaluate and document the quantitative performance of an assay, including sensitivity, specificity, accuracy, precision, detection limit, range and limits of. Multivariate concordance correlation coefficient a dissertation in statistics by sasiprapa hiriote c 2009 sasiprapa hiriote submitted in partial ful llment of the requirements for the degree of.
Estimation of the concordance correlation coefficient for. Like a correlation, ccc ranges from 1 to 1, with perfect agreement at 1. Evaluating intra and interexaminer reproducibility in histometric measurement. Comparison of two dependent within subject coefficients of. It is simple to use and possesses desirable properties. The total deviation index estimated by tolerance intervals.
Reproducibility and predictive value of scoring stromal. A new reproducibility index is developed and studied. Evaluating intra and interexaminer reproducibility in. Mcbride gb 2005 a proposal for strengthofagreement criteria for lins concordance correlation coefficient. A concordance correlation coefficient to evaluate reproducibility. Estimating felledtree stump volumes in the pacific northwest erik c. A sas macro and r package are provided here to estimate the concordance correlation coefficient ccc where the design of the data involves repeated. An alternative to the pearson correlation more suited for comparing diagnostic tests is the intraclass correlation coefficient icc.
Pdf estimation of the concordance correlation coefficient for. Use of the concordance correlation coefficient as a measure of reproducibility has gained popularity in practice since its introduction by lin 1989, biometrics 45, 255268. Lins concordance correlation coefficient correlation. Pdf a spatial concordance correlation coefficient with. How to compare the strengthsignificance of difference of.
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