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Generate lavaan CFA syntax from an instrument object

Source: R/psychometrics.R
cfa_syntax.Rd

Produces a character string of lavaan model syntax derived from the scale structure in the instrument. The syntax can be passed directly to lavaan::cfa(). Reverse-coded items are noted in a comment but are not transformed in the syntax; recoding should be applied to the data before fitting the model.

Usage

cfa_syntax(instrument, scales = NULL, std_lv = TRUE)

Arguments

instrument

An sframe object.

scales

Character vector or NULL. A subset of scale IDs to include. When NULL, all scales are included.

std_lv

Logical. Whether to include the std.lv = TRUE argument note in the output comment header. Defaults to TRUE.

Value

A character string of lavaan CFA model syntax.

See also

efa_report(), reliability_report()

Examples

cs    <- sf_choices("ag5", 1:5,
           c("Strongly disagree", "Disagree", "Neutral",
             "Agree", "Strongly agree"))
i1    <- sf_item("sat_1", "Item 1", type = "likert",
                 choice_set = "ag5", scale_id = "sat")
i2    <- sf_item("sat_2", "Item 2", type = "likert",
                 choice_set = "ag5", scale_id = "sat")
i3    <- sf_item("sat_3", "Item 3 (reverse)", type = "likert",
                 choice_set = "ag5", scale_id = "sat", reverse = TRUE)
scale <- sf_scale("sat", "Satisfaction",
                  items = c("sat_1", "sat_2", "sat_3"))
instr <- sf_instrument("Demo Survey", components = list(cs, i1, i2, i3, scale))

syntax <- cfa_syntax(instr)
cat(syntax)
#> # lavaan CFA syntax generated by surveyframe
#> # Model: Demo Survey CFA
#> # Recommended fitting option: std.lv = TRUE
#> # Fit with lavaan only when lavaan is installed.
#> 
#> # Satisfaction (reflective)
#> # Reverse-coded indicators: sat_3
#> sat =~ sat_1 + sat_2 + sat_3

if (FALSE) { # \dontrun{
# lavaan is not installed by default; install it before fitting.
demo   <- sframe_demo_data()
scored <- score_scales(demo$responses, demo$instrument)
fit    <- lavaan::cfa(syntax, data = scored, std.lv = TRUE)
summary(fit, fit.measures = TRUE)
} # }