It has versions for mac and windows, and it is currently at version 7. Instead, it is a process used to assess agreement between two methods of measurement. It plots the difference between the two measurements on the y axis, and the. This video describes how to contsruct and interpret a plot that can assess the level of agreement between two mesurement techniques using a numneric outcome. This macro produces a blandaltman plot of paired data.
It plots the difference between the two measurements on the y axis, and the average of the two measurements on the x axis. Blandaltman analysis as an alternative approach for. Bland altman analysis the bland altman analysis is not a statistical test measured with a pvalue. A bland altman plot compares two measures by plotting the score differences against the score averages. It can import excel, spss, dbase, lotus files, and files in. Although i watched all the videos about bland altman plot in spss, i could not find any information regarding how to. To see how these tools can benefit you, we recommend you download and install the free trial of ncss. Blandaltman method comparison using microsoft excel video.
You can download a free demo copy of medcalc software. Suppose there are two techniques for measuring some continuouslyscaled variable, each having some error, and we want a graphical means to assess whether or not they are comparable. Plots a blandaltman and correlation plot for two data sets, including data. Ncss includes easytouse tools for method comparison, including bland altman plot and analysis, deming regression, and passingbablok regression. Method comparison blandaltman plot deming regression ncss. Put your data into excel and use the formulae functions to calculate the. Plotted points beyond the loa are identified in red. Correlation between the itd and icg techniques was determined using linear regression. Bland and altman 1986, 2003 an important requirement of the bland altman method for measuring agreement is that the two methods for measuring the same characteristic use the same scale of measurement. Method comparison blandaltman plot deming regression. For more information and to download the tutorial examples, visit. The differences and averages of the data pairs are graphed with the center line and the limits of agreement loa.