Augmented CRD Calculator
Augmented CRD analysis online with checks and unreplicated entries. Adjusted means and SE.
When to use it
Use the augmented CRD when soil or environment is uniform (greenhouse, growth chamber, single-bench lab) so blocking adds nothing, and you have many test entries with limited seed plus a small set of replicated check varieties. The replicated checks anchor the error estimate; unreplicated test entries are evaluated by adjusted means.
When NOT to use it
Do not use when there is real spatial heterogeneity (use augmented RBD with blocks). Do not use when seed is sufficient to replicate every test entry; an RBD or alpha lattice gives more reliable comparisons. Do not use without checks; the unreplicated test entries cannot be evaluated against a noise estimate.
What you get
Adjusted means for every test entry; standard errors for test-vs-test, test-vs-check, and check-vs-check comparisons (each is a different SE because of how augmentation works); ANOVA on the checks; CV percent based on the check error; ranking table for the test entries.
How to interpret the output
Adjusted means are the right unit for ranking test entries. SE of test-vs-test is larger than SE of test-vs-check because test entries are unreplicated. Use the augmented CRD for screening (rank-order decisions); confirm top candidates in a replicated trial the next season. Federer 1956 is the original reference.
Common pitfalls
- Reading raw test means instead of adjusted means.
- Confusing the three SE values (test-test, test-check, check-check).
- Using the design when seed is sufficient for replication.
- Treating significant tests of test-vs-check as a complete answer; always re-test the top performers.
Try it in StatVeda
The Augmented Design (CRD, no blocks) engine runs entirely in the browser. No signup, no install, no data sent to a server. Paste your data, hit Run, copy the output.
Open Augmented Design (CRD, no blocks)References
- Federer, W. T. (1956). Augmented (or hoonuiaku) designs. Hawaiian Planters' Record, 55, 191 to 208.
- Federer, W. T. and Raghavarao, D. (1975). On augmented designs. Biometrics, 31(1), 29 to 35.
- Cochran, W. G. and Cox, G. M. (1957). Experimental Designs, 2nd edition. John Wiley and Sons, New York.