compatible.formula.terms {cvms}

Compatible formula terms

Description

162,660 pairs of compatible terms for building model formulas with up to 15 fixed effects.

Format

A data.frame with 162,660 rows and 5 variables:

left

term, fixed effect or interaction, with fixed effects separated by "*"

right

term, fixed effect or interaction, with fixed effects separated by "*"

max_interaction_size

maximum interaction size in the two terms, up to 3

num_effects

number of unique fixed effects in the two terms, up to 5

min_num_fixed_effects

minimum number of fixed effects required to use a formula with the two terms, i.e. the index in the alphabet of the last of the alphabetically ordered effects (letters) in the two terms, so 4 if left == "A" and right == "D"

Details

A term is either a fixed effect or an interaction between fixed effects (up to three-way), where the effects are separated by the "*" operator.

Two terms are compatible if they are not redundant, meaning that both add a fixed effect to the formula. E.g. as the interaction "x1 * x2 * x3" expands to "x1 + x2 + x3 + x1 * x2 + x1 * x3 + x2 * x3 + x1 * x2 * x3", the higher order interaction makes these "sub terms" redundant. Note: All terms are compatible with NA.

Effects are represented by the first fifteen capital letters.

Used to generate the model formulas for combine_predictors.

Author(s)

Ludvig Renbo Olsen, [e-mail]