Interobserver Agreement Continuous Variables

24 Sep , 2021   David  

It is often interesting to know whether measurements made by two (sometimes more than two) different observers or by two different techniques give similar results. This is called concordance or concordance or reproducibility between measurements. Such an analysis considers the pairs of measurements, either categorical or both numerically, each pair having been made on an individual (or a pathology slide or an X-ray). In statistics, inter-rater reliability (also referred to by different similar names such as Inter-Rater agreement, inter-rater concordance, inter-observer reliability, etc.) is the degree of consistency between evaluators. It is an assessment of homogeneity or consensus in the assessments of different judges. Later extensions of the approach included versions that could handle “partial credits” and ordinal scales. [7] These extensions converge with the family of intraclassical correlations (CIC), so there is a conceptually related possibility of estimating the reliability for each level of measurement, from the nominal cappa to the interval (ICC or ordinal kappa) through the interval (ICC or ordinal kappa) and the ratio (CIC). There are also variants that make it possible to study the concordance of evaluators on a number of points (for example. B two interviewers agree on depression values for all points of the same semi-structured interview for one case?) as well as evaluators x cases (for example.

B to what extent are two or more assessors suitable if 30 cases have a diagnosis of depression, yes/no – a dummy variable). Readers are referenced to the following documents that contain compliance measures: there are a number of statistics that can be used to determine the reliability of the Inter-Rater. Different statistics are adapted to different types of measures. Some options are the common probability of an agreement, cohens Kappa, Scotts Pi and the related fleiss-Kappa, inter-rater correlation, concordance correlation coefficient, intraclass correlation and Krippendorffs Alpha. If two instruments or techniques are used to measure the same variable on a continuous scale, Bland Altman diagrams can be used to estimate compliance. . . .