Estimate PID-5 scale reliability — reliability

Compute per-scale internal-consistency reliability — Cronbach's alpha and McDonald's omega — for the Personality Inventory for DSM-5: full version (PID-5, 220 items), short form (PID-5-SF, 100 items), brief form (PID-5-BF, 25 items), modified brief form (PID5BF+M, 36 items), Informant Form (PID-5-IRF, 218 items; Markon et al., 2013), or Forensic Faceted Brief Form (PID-5-FFBF, 100 items; Niemeyer et al., 2022). Reliability is estimated on the reverse-keyed item responses, at the facet level for FULL/SF/IRF/FFBF and the domain level for BF (the same scales score_pid5() outputs, before FULL/SF/IRF/FFBF domain aggregation). The FFBF facets are its 25 four-item facets in the SF's order (see score_pid5()). The IRF facets are the full form's 25, numbered by informant item and reverse-keyed as the APA IRF key's Facet Table marks (see score_pid5()). The BF version also returns a Total row covering all 25 items; note that this scale spans five heterogeneous domains, so its internal consistency is not comparable to a domain's and is reported without further interpretation.

Usage

reliability_pid5(
  data,
  items,
  version = c("FULL", "SF", "BF", "BFPM", "IRF", "FFBF"),
  srange = c(0, 3),
  alpha = TRUE,
  omega = TRUE
)

Arguments

data: A data frame containing (at least) all the PID items (numerically scored and in order).
items: A vector of column names (as strings) or numbers (as integers) corresponding to the PID items in order. Items must be supplied in instrument order; duplicated entries are an error. Each column must be numeric or logical, or character holding only numbers (blank cells and NA values count as missing, but the text "NA" is refused). A haven labelled column is read as its plain values. Any other column, such as the choice text of an online export or a factor, is an error of class hitop_nonnumeric_items. So is a 64-bit integer (integer64) column, and, in a UTF-8 session, a column holding text that is not valid UTF-8 (text marked Latin-1 is read as its text); convert such text with iconv(). So is an SPSS column (haven_labelled_spss) that holds a value it declares missing; turn those codes into NA with haven::zap_missing() first. A declared value that is blank is not refused, since blank cells count as missing. The SPSS class of haven before 2.0 (labelled_spss) is refused the same way, but haven::zap_missing() leaves it unchanged, so set the values its na_values or na_range attribute declares to NA first.
version: A string indicating the version of the PID to score: "FULL", "SF", "BF", "BFPM" (the 36-item PID5BF+M), "IRF" (the 218-item Informant Form), or "FFBF" (the 100-item Forensic Faceted Brief Form). Only a full name is accepted, in any letter case. Any other value, a start of a name such as "F" included, is an error of class hitop_unknown_version. (default = "FULL")
srange: An optional numeric vector specifying the minimum and maximum values of the items, used for reverse-coding. (default = c(0, 3))
alpha: Optional logical; if TRUE, include a column of Cronbach's alpha per scale. (default = TRUE)
omega: Optional logical; if TRUE, include a column of McDonald's omega (total) per scale, estimated via a one-factor CFA (requires the lavaan package). (default = TRUE)

Value

A tibble with one row per scale and columns Scale (the scale's canonical display name, as the instrument's keying table spells it), camelCase (the stem that names the scale's column in the matching score_*() output, read from the same keying-table row), nItems (integer), and (when requested) alpha and omega.

Details

The BFPM version returns both levels: its 18 two-item facets, then its 6 domains, each estimated over the 6 items of its 3 facets (the map is in pid_bfpm_domains). Omega is NA for every facet, because a one-factor model of 2 items is not identified; alpha is reported for all 24 rows.

Alpha is computed by calc_alpha() (covariance-based, pairwise deletion) and omega by calc_omega() (one-factor lavaan CFA, FIML). A scale whose estimate cannot be computed (e.g. too few items or, for omega, a non-converging CFA or an uninstalled lavaan) is returned as NA rather than aborting the call. Omega needs at least 3 items: for a scale with fewer, no model is fitted and omega is NA.

References

Markon, K. E., Quilty, L. C., Bagby, R. M., & Krueger, R. F. (2013). The development and psychometric properties of an informant-report form of the Personality Inventory for DSM-5 (PID-5). Assessment, 20(3), 370-383. doi:10.1177/1073191113486513 The scoring key for version = "IRF" is the APA's The Personality Inventory for DSM-5—Informant Form (PID-5-IRF)—Adult (2013).

Niemeyer, L. M., Grosz, M. P., Zimmermann, J., & Back, M. D. (2022). Assessing maladaptive personality in the forensic context: Development and validation of the Personality Inventory for DSM-5 Forensic Faceted Brief Form (PID-5-FFBF). Journal of Personality Assessment, 104(1), 30-43. doi:10.1080/00223891.2021.1923522 The source of version = "FFBF".

Examples

# Facet-level reliability for the full PID-5 (alpha only)
reliability_pid5(sim_pid5, items = 1:220, version = "FULL", omega = FALSE)
#> # A tibble: 25 × 4
#>    Scale                  camelCase             nItems   alpha
#>    <chr>                  <chr>                  <int>   <dbl>
#>  1 Anhedonia              anhedonia                  8 -0.211 
#>  2 Suspiciousness         suspiciousness             7 -0.211 
#>  3 Risk Taking            riskTaking                14 -0.0128
#>  4 Impulsivity            impulsivity                6  0.141 
#>  5 Eccentricity           eccentricity              13  0.0554
#>  6 Distractibility        distractibility            9 -0.154 
#>  7 Restricted Affectivity restrictedAffectivity      7 -0.144 
#>  8 Submissiveness         submissiveness             4 -0.194 
#>  9 Withdrawal             withdrawal                10 -0.0290
#> 10 Callousness            callousness               14  0.0147
#> # ℹ 15 more rows