Bland-Altman agreement
Shown in the app as bland_altman. Part of the method reference, under Diagnostic accuracy and agreement.
When to use
Agreement between two NUMERIC measurements of the same quantity (method comparison): bias (mean difference) and 95% limits of agreement, each with a confidence interval.
What you provide
- The two measurements of the same quantity: two numeric columns.
Options
Missing data
- Complete case (listwise deletion)
Multiple comparisons
- Not adjustable for this method. Where it makes post-hoc comparisons, the procedure applies its own correction.
Confidence level
Every interval in the result is reported at the level you choose:
- 90%
- 95%
- 99%
Related methods
Other methods under Diagnostic accuracy and agreement:
Guides that discuss this method
Worked examples
Celeus's result on a published or illustrative dataset, next to an independent computation and, where one exists, a published value. The data themselves are not reproduced here.
carData::Davis (measured vs self-reported weight)
- Source: Published dataset distributed with an R package
- Licence: carData (GPL)
- Reference: Davis (1990), from Fox & Weisberg, An R Companion to Applied Regression (carData)
| Quantity | Celeus | Independent computation | Published value | Agrees |
|---|---|---|---|---|
| Mean difference (bias) | 0.601093 | 0.601093 | - | Yes |
| Lower limit of agreement | -15.969 | -15.969 | - | Yes |
| Upper limit of agreement | 17.1711 | 17.1711 | - | Yes |
Bland & Altman (1986) Table 1 (Wright vs mini Wright peak flow, first readings)
- Source: Values entered from a table in the cited publication
- Licence: values entered from the published table
- Reference: Bland JM, Altman DG (1986), The Lancet 327(8476):307-310, Table 1
| Quantity | Celeus | Independent computation | Published value | Agrees |
|---|---|---|---|---|
| Mean difference (bias) | -2.11765 | -2.11765 | -2.1 | Yes |
| Standard deviation of the differences | 38.7651 | 38.7651 | 38.8 | Yes |
| Confidence interval for the mean difference | -22.0488, 17.8135 | -22.0488, 17.8135 | - | Yes |
Bland & Altman (1986) Table 1 (Wright vs mini Wright peak flow, first readings; 90% intervals)
- Source: Values entered from a table in the cited publication
- Licence: values entered from the published table
- Reference: Bland JM, Altman DG (1986), The Lancet 327(8476):307-310, Table 1
| Quantity | Celeus | Independent computation | Published value | Agrees |
|---|---|---|---|---|
| Confidence interval for the mean difference | -18.5323, 14.2970 | -18.5323, 14.2970 | - | Yes |
ggplot2::diamonds (length x vs width y, mm)
- Source: Published dataset distributed with an R package
- Licence: ggplot2 (MIT)
- Reference: ggplot2::diamonds, from Wickham, ggplot2: Elegant Graphics for Data Analysis (ggplot2 package)
| Quantity | Celeus | Independent computation | Published value | Agrees |
|---|---|---|---|---|
| Mean difference (bias) | -0.00336874 | -0.00336874 | - | Yes |
| Confidence interval for the mean difference | -0.00552430, -0.00121318 | -0.00552430, -0.00121318 | - | Yes |
| p-value | 0.0021914 | 0.0021914 | - | Yes |
References
- Bland, J. M., Altman, D. G. (1986). Statistical methods for assessing agreement between two methods of clinical measurement. The Lancet 327: 307-310. doi:10.1016/S0140-6736(86)90837-8 doi:10.1016/S0140-6736(86)90837-8
- Bland, J. M., Altman, D. G. (1999). Measuring agreement in method comparison studies. Statistical Methods in Medical Research 8: 135-160. doi:10.1177/096228029900800204 doi:10.1177/096228029900800204