Randomised Complete Block Design
A randomised complete block design where every treatment appears exactly once in each block. Treatments are randomly allocated to plots within each block independently.
Design Reference — what this design is, parameters explained, output guide
Randomised Complete Block Design
Treatments are randomly allocated within each block. Every block contains exactly one replicate of each treatment. The block structure controls for a known source of variability (e.g. field gradient, time, operator).
Use when: You can group experimental units into blocks that are internally homogeneous. Blocking removes known variability from the error term, increasing the power to detect treatment differences.
Parameters
| Parameter | Type | Default | Min | Max | Description |
|---|---|---|---|---|---|
experiment_name |
text | "" |
— | — | Name of the experiment |
treatment_factor |
text | "Variety" |
— | — | Label for the treatment factor column |
treatment_count |
integer | 2 |
2 | 500 | Number of distinct treatments |
block_factor |
text | "Block" |
— | — | Label for the blocking factor column |
block_count |
integer | 2 |
1 | 100 | Number of blocks (= number of replicates per treatment) |
unit_label |
text | "Plot" |
— | — | Label for each experimental unit |
treatment_names |
list | None |
— | — | Optional custom treatment names (comma-separated) |
seed |
integer | 0 |
— | — | Random seed |
Constraints
- Total units =
treatment_count × block_countmust not exceed 5,000
Output
List View
| Column | Description |
|---|---|
| Unit | Sequential unit number across the whole experiment |
| block_factor (e.g. Block) | Which block this unit belongs to |
| unit_label (e.g. Plot) | Plot number within the block |
| treatment_factor (e.g. Variety) | Treatment allocated to this unit |
Layout View
A grid showing the spatial/sequential arrangement: - Rows = plots within a block - Columns = blocks
Total units: treatment_count × block_count
Algorithm
- For each block independently:
- Create a list of all treatments
- Randomly permute the list
- Assign sequential plot numbers within the block
- Number units sequentially across all blocks
Example
With treatment_count = 3, block_count = 2, treatments T1/T2/T3:
| Unit | Block | Plot | Variety |
|---|---|---|---|
| 1 | Block 1 | 1 | T3 |
| 2 | Block 1 | 2 | T1 |
| 3 | Block 1 | 3 | T2 |
| 4 | Block 2 | 1 | T2 |
| 5 | Block 2 | 2 | T3 |
| 6 | Block 2 | 3 | T1 |
Each treatment appears exactly once per block, in a random order within each block.