A review of agreement measure as a subset of association measure between raters

Agreement can be regarded as a special case of association and not the other way round. Virtually in all life or social science researches, subjects are being classified into categories by raters, interviewers or observers and both association and agreement measures can be obtained from the results of this researchers. The distinction between association and agreement for a given data is that, for two responses to be perfectly associated we require that we can predict the category of one response from the category of the other response, while for two response to agree, they must fall into the identical category. Which hence mean, once there is agreement between the two responses, association has already exist, however, strong association may exist between the two responses without any strong agreement. Many approaches have been proposed by various authors for measuring each of these measures. In this work, we present some up till date development on these measures statistics

The Many-to-Many Mapping Between the Concordance Correlation Coefficient and the Mean Square Error

We derive the mapping between two of the most pervasive utility functions, the mean square error ($MSE$) and the concordance correlation coefficient (CCC, $\rho_c$). Despite its drawbacks, $MSE$ is one of the most popular performance metrics (and a loss function); along with lately $\rho_c$ in many of the sequence prediction challenges. Despite the ever-growing simultaneous usage, e.g., inter-rater agreement, assay validation, a mapping between the two metrics is missing, till date. While minimisation of $L_p$ norm of the errors or of its positive powers (e.g., $MSE$) is aimed at $\rho_c$ maximisation, we reason the often-witnessed ineffectiveness of this popular loss function with graphical illustrations. The discovered formula uncovers not only the counterintuitive revelation that `$MSE_1<MSE_2$' does not imply `$\rho_{c_1}>\rho_{c_2}$', but also provides the precise range for the $\rho_c$ metric for a given $MSE$. We discover the conditions for $\rho_c$ optimisation for a given $MSE$; and as a logical next step, for a given set of errors. We generalise and discover the conditions for any given $L_p$ norm, for an even p. We present newly discovered, albeit apparent, mathematical paradoxes. The study inspires and anticipates a growing use of $\rho_c$-inspired loss functions e.g., $\left|\frac{MSE}{\sigma_{XY}}\right|$, replacing the traditional $L_p$-norm loss functions in multivariate regressions.Comment: Why this discovery, or the mapping formulation is important: MSE1CCC2. In other words, MSE minimisation does not necessarily guarantee CCC maximisatio

Excellent intra and inter-observer reproducibility of wrist circumference measurements in obese children and adolescents

In a previous study, we found that wrist circumference, in particular its bone component,was associated with insulin resistance in a population of overweight/obese children. Theaim of the present study was to evaluate the intra- and inter-operator variability in wrist cir-cumference measurement in a population of obese children and adolescents. One hundredand two (54 male and 48 female) obese children and adolescents were consecutivelyenrolled. In all subjects wrist circumferences were measured by two different operators twotimes to assess intra- and inter-operator variability. Statistical analysis was performed usingSAS v.9.4 and JMP v.12. Measurements of wrist circumference showed excellent inter-operator reliability with Intra class Correlation Coefficients (ICC) of 0.96 and ICC of 0.97 forthe first and the second measurement, respectively. The intra-operator reliability was, also,very strong with a Concordance Correlation Coefficient (CCC) of 0.98 for both operators.The high reproducibility demonstrated in our results suggests that wrist circumference mea-surement, being safe, non-invasive and repeatable can be easily used in out-patient set-tings to identify youths with increased risk of insulin-resistance. This can avoid testing theentire population of overweight/obese children for insulin resistance parameter

Optimal Clinical Time for Reliable Measurement of Transcutaneous CO2 with Ear Probes: Counterbalancing Overshoot and the Vasodilatation Effect

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Reliability of countermovement jump estimation using the Chronojump jump mat: intra-session and within-session

Vertical jump is a fundamental metric for monitoring and regulating lower body capacities, especially in assessing sports performance through the countermovement jump (CMJ). In recent years, various instruments aimed at estimating vertical jump heights have emerged. However, ensuring effective performance monitoring requires that jump mats prove consistency in measuring jumps across repeated tests, i.e., they must prove reliability. This study focuses on evaluating the intra-session and within-session test-retest reliability of the Chronojump jump mat in highly trained female volleyball players. Ten athletes from the Spanish Superliga 2 league participated in 100 CMJs over two sessions spaced a week apart. A repeated measures design collected jump height data using Chronojump jump mat. The protocol included a 10-min warm-up, a 5-min rest, and the execution of 5 CMJs with 2 min of rest between trials. Intra-session test-retest consistency was assessed by analyzing consecutive pairings of the first five trials. The study reveals moderate noise for SEM (1.56 cm) and standardized SEM (0.37), accompanied high SDC (4.33 cm) and SWC (0.44 cm). Correlation analysis indicated very high reliability (ICC =0.89), high concordance (CCC = 0.82) and a moderate CV (5.97%). Regarding within-session reliability, no significant differences were observed (Paired t-test p = 0.08; Hedges effect size g = 0.09). Additionally, very high correlations between both sessions were observed (r = 0.86). Absolute reliability analysis revealed a noise of 1.65 cm (SEM), resulting in high SDC (4.59 cm) and SWC (0.47 cm). Relative reliability, assessed through correlation coefficients, displayed very high values (ICC = 0.89 and CCC =0.89), although a moderate standardized SEM of 0.44 was observed. The Bland-Altman plot indicated systematic errors of the mean of 0.41 cm without substantial dispersion. Linear regression analyses between sessions showed a high correlation (r = 0.86), with a systematic error of 6.65 cm (intercept) and a random error of 2.01 cm (SEE). To sum up, the Chronojump jump mat proves reliability in measuring CMJ in female volleyball players across both intra-session and within-session contexts. High reliability suggests that this instrument can be deemed reliable for such measurements.This work was supported by Generalitat Valenciana (grant number GV/2021/098). Article developed during Dr. Jimenez-Olmedo's research intership with the Sports Biomechanics Research Group (GIBD) (GIUV2019-454) at University of Valencia