seq_balmin_rmd: Afsarinejad (1983) cross-over design specification
In mjg211/xover: Design and analysis of cross-over clinical trials

Description Usage Arguments Details Value Author(s) References Examples

Specifies cross-over designs from Afsarinejad (1983).

1 2	seq_balmin_rmd(D = 2, J = 2, labels = 0:(D - 1), as_matrix = T, summary = T)

`D`	The number of treatments. Must be a single `numeric` integer greater than or equal to two. Defaults to `2`.
`J`	The number of periods. Must be a single `numeric` integer less than or equal to `D`. Defaults to `2`.
`labels`	A `vector` of labels for the treatments. Should be of `length` `D`, containing unique elements. Defaults to `0:(D - 1)`.
`as_matrix`	A `logical` variable indicating whether the design should be returned as a `matrix`, or a `tibble`. Defaults to `T`.
`summary`	A `logical` variable indicating whether a summary of the function's progress should be printed to the console. Defaults to `T`.

seq_balmin_rmd() supports the specification of cross-over designs from Afsarinejad (1983). Designs for any number of treatments (see D) are supported, for any chosen treatment labels (see labels). The number of periods (see J) can be any number such that (D - 1)/(J - 1) is a positive integer. In addition, the designs can be returned in matrix or tibble form (see as_matrix).

Precisely, a balanced minimal repeated measurement design is returned. The sequences are incomplete, i.e., no sequence contains all of the treatments. The design is balanced for carryover effects but will in general not be a balanced block design. A necessary and sufficient condition for the existence of such a design is that (D - 1)/(J - 1) is a positive integer: this is therefore enforced by the function. The number of sequences, K, in the resulting design is D(D - 1)/(J - 1). Ultimately, the (k,j)th element of the cross-over design matrix corresponds to the treatment a subject on the kth sequence would receive in the jth period.

Either a matrix if as_matrix = T (with rows corresponding to sequences and columns to periods), or a tibble if as_matrix = F (with rows corresponding to a particular period on a particular sequence). In either case, the returned object will have class xover_seq.

Based on code from the crossdes package by Oliver Sailer.

Afsarinejad K (1983) Balanced repeated measurements designs. Biometrika 70:199-204.

Wakeling IN, MacFie HJH (1995) Designing consumer trials balanced for first and higher orders of carry-over effect when only a subset of k samples from t may be tested. Food Qual Prefer 6:299-308.

# Afsarinejad (1983) design for four treatments and two periods
balmin_rmd        <- seq_balmin_rmd()
# Using different labels
balmin_rmd_ABCD   <- seq_balmin_rmd(labels = LETTERS[1:4])
# Returning in tibble form
balmin_rmd_tibble <- seq_balmin_rmd(as_matrix = F)