Graph description: Comparing methods of measurement: why plotting difference against standard method is misleading, 2
The figure shows a plot of the difference, finger systolic blood pressure minus arm systolic blood pressure,
against the average of finger systolic blood pressure and arm systolic blood pressure.
Difference is on the vertical axis, average on the horizontal axis.
Each point is plotted as a circle.
There is a fairly weak positive relationship.
The regression line of difference and average is shown on the graph. This has a small positive gradient.
Also shown are the 95% limits of agreement, horizontal dotted lines.
These include between them most of the observations.
Comparing methods of measurement: why plotting difference against standard method is misleading.
This page maintained by Martin Bland.
Last updated: 12 January, 2004.