Package 'unusualprofile'

Title: Calculates Conditional Mahalanobis Distances
Description: Calculates a Mahalanobis distance for every row of a set of outcome variables (Mahalanobis, 1936 <doi:10.1007/s13171-019-00164-5>). The conditional Mahalanobis distance is calculated using a conditional covariance matrix (i.e., a covariance matrix of the outcome variables after controlling for a set of predictors). Plotting the output of the cond_maha() function can help identify which elements of a profile are unusual after controlling for the predictors.
Authors: W. Joel Schneider [aut, cre] , Feng Ji [aut]
Maintainer: W. Joel Schneider <[email protected]>
License: GPL (>= 3)
Version: 0.1.4
Built: 2025-02-11 05:28:30 UTC
Source: https://github.com/wjschne/unusualprofile

Help Index


Calculate the conditional Mahalanobis distance for any variables.

Description

Calculate the conditional Mahalanobis distance for any variables.

Usage

cond_maha(
  data,
  R,
  v_dep,
  v_ind = NULL,
  v_ind_composites = NULL,
  mu = 0,
  sigma = 1,
  use_sample_stats = FALSE,
  label = NA
)

Arguments

data

Data.frame with the independent and dependent variables. Unless mu and sigma are specified, data are assumed to be z-scores.

R

Correlation among all variables.

v_dep

Vector of names of the dependent variables in your profile.

v_ind

Vector of names of independent variables you would like to control for.

v_ind_composites

Vector of names of independent variables that are composites of dependent variables

mu

A vector of means. A single value means that all variables have the same mean.

sigma

A vector of standard deviations. A single value means that all variables have the same standard deviation

use_sample_stats

If TRUE, estimate R, mu, and sigma from data. Only complete cases are used (i.e., no missing values in v_dep, v_ind, v_ind_composites).

label

optional tag for labeling output

Value

a list with the conditional Mahalanobis distance

  • dCM = Conditional Mahalanobis distance

  • dCM_df = Degrees of freedom for the conditional Mahalanobis distance

  • dCM_p = A proportion that indicates how unusual this profile is compared to profiles with the same independent variable values. For example, if dCM_p = 0.88, this profile is more unusual than 88 percent of profiles after controlling for the independent variables.

  • dM_dep = Mahalanobis distance of just the dependent variables

  • dM_dep_df = Degrees of freedom for the Mahalanobis distance of the dependent variables

  • dM_dep_p = Proportion associated with the Mahalanobis distance of the dependent variables

  • dM_ind = Mahalanobis distance of just the independent variables

  • dM_ind_df = Degrees of freedom for the Mahalanobis distance of the independent variables

  • dM_ind_p = Proportion associated with the Mahalanobis distance of the independent variables

  • v_dep = Dependent variable names

  • v_ind = Independent variable names

  • v_ind_singular = Independent variables that can be perfectly predicted from the dependent variables (e.g., composite scores)

  • v_ind_nonsingular = Independent variables that are not perfectly predicted from the dependent variables

  • data = data used in the calculations

  • d_ind = independent variable data

  • d_inp_p = Assuming normality, cumulative distribution function of the independent variables

  • d_dep = dependent variable data

  • d_dep_predicted = predicted values of the dependent variables

  • d_dep_deviations = d_dep - d_dep_predicted (i.e., residuals of the dependent variables)

  • d_dep_residuals_z = standardized residuals of the dependent variables

  • d_dep_cp = conditional proportions associated with standardized residuals

  • d_dep_p = Assuming normality, cumulative distribution function of the dependent variables

  • R2 = Proportion of variance in each dependent variable explained by the independent variables

  • zSEE = Standardized standard error of the estimate for each dependent variable

  • SEE = Standard error of the estimate for each dependent variable

  • ConditionalCovariance = Covariance matrix of the dependent variables after controlling for the independent variables

  • distance_reduction = 1 - (dCM / dM_dep) (Degree to which the independent variables decrease the Mahalanobis distance of the dependent variables. Negative reductions mean that the profile is more unusual after controlling for the independent variables. Returns 0 if dM_dep is 0.)

  • variability_reduction = 1 - sum((X_dep - predicted_dep) ^ 2) / sum((X_dep - mu_dep) ^ 2) (Degree to which the independent variables decrease the variability the dependent variables (X_dep). Negative reductions mean that the profile is more variable after controlling for the independent variables. Returns 0 if X_dep == mu_dep)

  • mu = Variable means

  • sigma = Variable standard deviations

  • d_person = Data frame consisting of Mahalanobis distance data for each person

  • d_variable = Data frame consisting of variable characteristics

  • label = label slot

Examples

library(unusualprofile)
library(simstandard)

m <- "
Gc =~ 0.85 * Gc1 + 0.68 * Gc2 + 0.8 * Gc3
Gf =~ 0.8 * Gf1 + 0.9 * Gf2 + 0.8 * Gf3
Gs =~ 0.7 * Gs1 + 0.8 * Gs2 + 0.8 * Gs3
Read =~ 0.66 * Read1 + 0.85 * Read2 + 0.91 * Read3
Math =~ 0.4 * Math1 + 0.9 * Math2 + 0.7 * Math3
Gc ~ 0.6 * Gf + 0.1 * Gs
Gf ~ 0.5 * Gs
Read ~ 0.4 * Gc + 0.1 * Gf
Math ~ 0.2 * Gc + 0.3 * Gf + 0.1 * Gs"
# Generate 10 cases
d_demo <- simstandard::sim_standardized(m = m, n = 10)

# Get model-implied correlation matrix
R_all <- simstandard::sim_standardized_matrices(m)$Correlations$R_all

cond_maha(data = d_demo,
          R = R_all,
          v_dep = c("Math", "Read"),
          v_ind = c("Gf", "Gs", "Gc"))

An example data.frame

Description

A dataset with 1 row of data for a single case.

Usage

d_example

Format

A data frame with 1 row and 8 variables:

X_1

A predictor variable

X_2

A predictor variable

X_3

A predictor variable

Y_1

An outcome variable

Y_2

An outcome variable

Y_3

An outcome variable

X

A latent predictor variable

Y

A latent outcome variable


Plot the variables from the results of the cond_maha function.

Description

Plot the variables from the results of the cond_maha function.

Usage

## S3 method for class 'cond_maha'
plot(
  x,
  ...,
  p_tail = 0,
  family = "sans",
  score_digits = ifelse(min(x$sigma) >= 10, 0, 2)
)

Arguments

x

The results of the cond_maha function.

...

Arguments passed to print function

p_tail

The proportion of the tail to shade

family

Font family.

score_digits

Number of digits to round scores.

Value

A ggplot2-object


Plot objects of the maha class (i.e, the results of the cond_maha function using dependent variables only).

Description

Plot objects of the maha class (i.e, the results of the cond_maha function using dependent variables only).

Usage

## S3 method for class 'maha'
plot(
  x,
  ...,
  p_tail = 0,
  family = "sans",
  score_digits = ifelse(min(x$sigma) >= 10, 0, 2)
)

Arguments

x

The results of the cond_maha function.

...

Arguments passed to print function

p_tail

Proportion in violin tail (defaults to 0).

family

Font family.

score_digits

Number of digits to round scores.

Value

A ggplot2-object


Rounds proportions to significant digits both near 0 and 1

Description

Rounds proportions to significant digits both near 0 and 1

Usage

proportion_round(p, digits = 2)

Arguments

p

probability

digits

rounding digits

Value

numeric vector

Examples

proportion_round(0.01111)

Rounds proportions to significant digits both near 0 and 1, then converts to percentiles

Description

Rounds proportions to significant digits both near 0 and 1, then converts to percentiles

Usage

proportion2percentile(
  p,
  digits = 2,
  remove_leading_zero = TRUE,
  add_percent_character = FALSE
)

Arguments

p

probability

digits

rounding digits. Defaults to 2

remove_leading_zero

Remove leading zero for small percentiles, Defaults to TRUE

add_percent_character

Append percent character. Defaults to FALSE

Value

character vector

Examples

proportion2percentile(0.01111)

An example correlation matrix

Description

A correlation matrix used for demonstration purposes It is the model-implied correlation matrix for this structural model: X =~ 0.7 * X_1 + 0.5 * X_2 + 0.8 * X_3 Y =~ 0.8 * Y_1 + 0.7 * Y_2 + 0.9 * Y_3 Y ~ 0.6 * X

Usage

R_example

Format

A matrix with 8 rows and 8 columns:

X_1

A predictor variable

X_2

A predictor variable

X_3

A predictor variable

Y_1

An outcome variable

Y_2

An outcome variable

Y_3

An outcome variable

X

A latent predictor variable

Y

A latent outcome variable