# Scatter plot (method comparison)

A scatter plot shows the relationship between two methods.

The scatter plot shows measured values of the reference or comparison method on the horizontal axis, against the test method on the vertical axis.

The relationship between the methods may indicate a constant, or proportional bias, and the variability in the measurements across the measuring interval. If the points form a constant-width band, the method has a constant standard deviation (constant SD). If the points form a band that is narrower at small values and wider at large values, there is a constant relationship between the standard deviation and value, and the method has constant a coefficient of variation (CV). Some measurement procedures exhibit constant SD in the low range and constant CV in the high range.

If both methods measure on the same scale, a gray identity line shows ideal agreement and is useful for comparing the relationship against.

- What is Analyse-it?
- Administrator's Guide
- User's Guide
- Statistical Reference Guide
- Distribution
- Compare groups
- Compare pairs
- Contingency tables
- Correlation and association
- Principal component analysis (PCA)
- Factor analysis (FA)
- Item reliability
- Fit model
- Method comparison
- Correlation coefficient
- Scatter plot
- Fit Y on X
- Fitting ordinary linear regression
- Fitting Deming regression
- Fitting Passing-Bablok regression
- Linearity
- Residual plot
- Checking the assumptions of the fit
- Average bias
- Estimating the bias between methods at a decision level
- Testing commutability of other materials
- Difference plot (Bland-Altman plot)
- Fit differences
- Plotting a difference plot and estimating the average bias
- Limits of agreement (LoA)
- Plotting the Bland-Altman limits of agreement
- Mountain plot (folded CDF plot)
- Plotting a mountain plot
- Partitioning and reducing the measuring interval
- Study design
- Measurement systems analysis (MSA)
- Reference interval
- Diagnostic performance
- Control charts
- Process capability
- Pareto analysis
- Study Designs
- Bibliography

Version 5.40

Published 29-Jul-2019