estimate_design: Estimate single-case design

In scan: Single-Case Data Analyses for Single and Multiple Baseline Designs

Estimate single-case design

Description

This functions takes an scdf and extracts design parameters. The resulting object can be used to randomly create new scdf files with the same underlying parameters. This is useful for Monte-Carlo studies and bootstrapping procedures.

Usage

estimate_design(
  data,
  dvar,
  pvar,
  mvar,
  s = NULL,
  rtt = NULL,
  overall_effects = FALSE,
  overall_rtt = TRUE,
  model = "JW",
  ...
)

Arguments

data	A single-case data frame. See scdf() to learn about this format.
dvar	Character string with the name of the dependent variable. Defaults to the attributes in the scdf file.
pvar	Character string with the name of the phase variable. Defaults to the attributes in the scdf file.
mvar	Character string with the name of the measurement time variable. Defaults to the attributes in the scdf file.
s	The standard deviation depicting the between case variance of the overall performance. If more than two single-cases are included in the scdf, the variance is estimated if s is set to NULL. If s is provided, this value is used.
rtt	The reliability of the measurements. The reliability is estimated when rtt = NULL. If rtt is provided, this value is used for all single-cases.
overall_effects	If TRUE, trend, level, and slope effect estimations will be identical for each case. If FALSE, effects are estimated for each case separately. Default is FALSE.
overall_rtt	Ignored when rtt is set. If TRUE, rtt estimations will be based on all cases and identical for each case. If FALSE rtt is estimated for each case separately. Default is TRUE.
model	Model used for calculating the dummy parameters (see Huitema & McKean, 2000). Default is model = "W". Possible values are: "B&L-B", "H-M", "W", and deprecated "JW".
...	Further arguments passed to the plm function used for parameter estimation. For example, the model argument can be used to select different piecewise regression models. See plm for details.

Details

The function uses the plm function to estimate parameters for each single-case. If more than two single-cases are included in the scdf, the between case variance depicting the overall performance (s) is estimated unless s is provided. The reliability of the measurements (rtt) is estimated for each case unless rtt is provided. If overall_rtt is set to TRUE, rtt estimations will be based on all cases and identical for each case. If overall_effects is set to TRUE, trend, level, and slope effect estimations will be identical for each case.

The resulting design object can be used as input for the random_scdf function to create new random scdf files based on the estimated parameters. This allows to create bootstrap samples or Monte-Carlo datasets based on the characteristics of an existing dataset.

Value

A list of parameters for each single-case. Parameters include name, length, and starting measurement time of each phase, trend, level, and slope effects for each phase, start value, standard deviation, and reliability for each case. This list can be used as input for the random_scdf function to create new random scdf files based on the estimated parameters.

Author(s)

Juergen Wilbert

Examples

# create a random scdf with predefined parameters
set.seed(1234)
design <- design(
  n = 10, trend = -0.02,
  level = list(0, 1), rtt = 0.8,
  s = 1
)
scdf<- random_scdf(design)

# Estimate the parameters based on the scdf and create a new random scdf
# based on these estimations
design_est <- estimate_design(scdf, rtt = 0.8)
scdf_est <- random_scdf(design_est)

# Analyze both datasets with an hplm model. See how similar the estimations
# are:
hplm(scdf, slope = FALSE)
hplm(scdf_est, slope = FALSE)

# Also similar results for pand and randomization tests:
pand(scdf)
pand(scdf_est)
rand_test(scdf)
rand_test(scdf_est)

scan documentation built on April 1, 2026, 9:06 a.m.