Two-Factor Randomised Complete Block Design
A randomised complete block design with two crossed treatment factors. All combinations of factor A and factor B levels appear once in each block and are randomly allocated to plots.
Design Reference — what this design is, parameters explained, output guide
Two-Factor Randomised Complete Block Design
Two treatment factors are crossed, producing all combinations of Factor A × Factor B levels. These treatment combinations are randomly allocated within each block.
Use when: You want to study the effects of two factors simultaneously, and test whether they interact. Blocking controls for a known source of variability.
Parameters
| Parameter | Type | Default | Min | Max | Description |
|---|---|---|---|---|---|
experiment_name |
text | "" |
— | — | Name of the experiment |
factor_a |
text | "Treatment1" |
— | — | Label for the first treatment factor |
factor_a_count |
integer | 2 |
2 | 100 | Number of levels of Factor A |
factor_b |
text | "Treatment2" |
— | — | Label for the second treatment factor |
factor_b_count |
integer | 2 |
2 | 100 | Number of levels of Factor B |
block_factor |
text | "Block" |
— | — | Label for the blocking factor |
block_count |
integer | 2 |
1 | 100 | Number of blocks (= replicates of the full factorial) |
unit_label |
text | "Plot" |
— | — | Label for each experimental unit |
factor_a_names |
list | None |
— | — | Optional custom names for Factor A levels |
factor_b_names |
list | None |
— | — | Optional custom names for Factor B levels |
seed |
integer | 0 |
— | — | Random seed |
Constraints
- Total units =
factor_a_count × factor_b_count × block_countmust not exceed 5,000
Output
List View
| Column | Description |
|---|---|
| Unit | Sequential unit number |
| block_factor | Which block this unit belongs to |
| unit_label | Plot number within the block |
| factor_a | Factor A level for this unit |
| factor_b | Factor B level for this unit |
Layout View
One section per block, each showing: - Plot number, Factor A level, Factor B level
Total units: factor_a_count × factor_b_count × block_count
What are Factor A and Factor B?
- Factor A might be, for example, irrigation level (irrigated / non-irrigated)
- Factor B might be fertiliser rate (low / medium / high)
- All combinations appear in every block: irrigated+low, irrigated+medium, irrigated+high, non-irrigated+low, etc.
This design allows you to estimate: - The main effect of Factor A (averaged over Factor B levels) - The main effect of Factor B (averaged over Factor A levels) - The interaction between A and B (whether the effect of A differs across levels of B)
Algorithm
- Create all
factor_a_count × factor_b_counttreatment combinations - For each block, randomly permute the list of combinations
- Assign unit and plot numbers sequentially