ABSTRACT In determining rater (instrument) reliability many techniques are available. A main discrimination between methods is made by the level of measurement (binary, categorical, continuous). Most techniques, such as the Mean Absolute Difference (MAD) or the Intraclass Correlation Analysis (ICC), apply to continuous data. Two other analysis methods are equivalence t-tests (quantitatively det...

Model validation is recognised as crucial to microsimulation modelling. However, modellers encounter difficulty in choosing the most meaningful methods to compare simulated and actual values. The aim of this paper is to introduce and demonstrate a method employed widely in healthcare calibration studies. The ‘Bland-Altman plot’ consists of a plot of the difference between two methods against th...

OBJECTIVES The Bland-Altman method is the most popular method used to assess the agreement of medical instruments. The main concern about this method is the presence of proportional bias. The slope of the regression line fitted to the Bland-Altman plot should be tested to exclude proportional bias. The aim of this study was to determine whether the overestimation of bias in the Bland-Altman ana...

In a contemporary clinical laboratory it is very common to have to assess the agreement between two quantitative methods of measurement. The correct statistical approach to assess this degree of agreement is not obvious. Correlation and regression studies are frequently proposed. However, correlation studies the relationship between one variable and another, not the differences, and it is not r...

Purpose: To compare the Intra Ocular Pressure (IOP) measurements obtained by Applanation Tonometer (AT) & Rebound Tonometer (RT). Methods: The Central Corneal Thickness (CCT) corrected IOP of 100 eyes were measured using first with RT (I Care) followed by AT (GAT). Results were compared statistically using Bland –Altman plot & Deming’s regression analysis. Results: Scatter plot analysis showed ...

Figure 3. Bland-Altman plot between total serum cortisol and free serum cortisol (57 patients). Limits of agreement, 2 33.966 to 2 4.596; mean difference, 2 19.281; 95% CI, 2 21.229 to 2 17.333; range, 2.495-25.825; Pitman test r , 2 0.981; P 5 0.001. diffi cult and time consuming (see the “Discussion” section in original article 1 ). Even more important is the observation that the degree of ag...