Derive the lmer formula implied by a specification

Construct the mixed-model formula (with response .y, as produced by model_data()) from the fixed-effect coefficients and random-effects structure of a specification. Interaction coefficients written a:b become formula terms a_b.

Usage

model_formula(spec)

Arguments

spec

A design specification (path or list).

Value

A stats::formula object suitable for fitting with lme4 or lmerTest.

Examples

spec <- build_spec(list(name = "d", seed = 1, design_kind = "within",
  include_items = TRUE, n_subject = 10, n_item = 8, factor_name = "cond",
  lev1 = "a", lev2 = "b", intercept = 6, effect = 0.05,
  subj_int_sd = 0.12, subj_slope_sd = 0.04, subj_corr = 0.2,
  item_int_sd = 0.08, item_slope_sd = 0.02, item_corr = -0.1,
  family = "shifted_lognormal", resp_name = "", sigma = 0.3, shift = 200))
model_formula(spec)
#> .y ~ effect + (1 + effect | subject) + (1 + effect | item)