Designs with complex blocking structures and network effects for use in agricultural field experiments

12/24/2020
by   Vasiliki Koutra, et al.
0

We propose a novel model-based approach for constructing optimal designs with complex blocking structures and network effects, for application in agricultural field experiments. The potential interference among plots is viewed as a network structure, defined via the adjacency matrix, which performs two functions: capturing the spatial structure to reflect distances between neighbouring plots across space and adjusting for farmer operations. We consider a field trial run at Rothamsted Research and provide a comparison of optimal designs under various different models, including the commonly used designs in such situations. It is shown that when there is interference between treatments on neighbouring plots, due to the spatial arrangement of the plots, such designs are at least as good as, and often even more efficient than, randomised row-column designs. The advantage of network designs is that we can construct the neighbouring structure even for an irregular layout by means of a graph to address the particular characteristics of the experiment. The need for such designs arises when control of heterogeneity is required. Ignoring the neighbouring structure can lead to imprecise estimates of the treatment parameters and invalid conclusions.

READ FULL TEXT
POST COMMENT

Comments

There are no comments yet.

Authors

page 4

page 6

02/26/2018

A graph-theoretic framework for algorithmic design of experiments

In this paper, we demonstrate that considering experiments in a graph-th...
02/04/2019

Optimal block designs for small experiments on networks

We propose a method for constructing optimal block designs for experimen...
07/09/2019

Optimal experimental designs for treatment contrasts in heteroscedastic models with covariates

In clinical trials, the response of a given subject often depends on the...
10/14/2019

Optimal Paired Comparison Block Designs

For paired comparison experiments involving competing options described ...
11/06/2018

Copula-based robust optimal block designs

Blocking is often used to reduce known variability in designed experimen...
08/17/2018

Mixed-Level Column Augmented Uniform Designs

In follow-up designs, some additional factors with two or three levels m...
05/31/2018

Near-Balanced Incomplete Block Designs with An Application to Poster Competitions

Judging scholarly posters creates a challenge to assign the judges effic...
This week in AI

Get the week's most popular data science and artificial intelligence research sent straight to your inbox every Saturday.