scdf: Single case data frame

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

Description

The class scdf stores single-case study data with one or more single-cases.

Usage

makeSCDF(data, B.start = NULL, MT = NULL)

scdf(
  values,
  B.start,
  mt,
  phase,
  phase.design,
  name,
  dvar = "values",
  pvar = "phase",
  mvar = "mt",
  ...
)

Arguments

data	A single-case data frame. See scdf to learn about this format.
B.start	The first measurement of phase B (simple coding if design is strictly AB).
MT	Deprecated: Measurement times
values	A vector containing measurement values of the dependent variable.
mt	A vector defining measurement times. Default is mt = (1,2,3,...,n).
phase	A vector defining phase assignments.
phase.design	A vector defining the length and label of each phase. E.g., phase.length = c(A1 = 10, B1 = 10, A2 = 10, B2 = 10).
name	A name for the case.
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.
...	Additional variables. E.g., teacher = c(0,1,0,1,0,0,1), lesson = c(1,3,4,5,2,3).

Details

The scdf class is a wrapper for a list containing a dataframe for each case.

If the dependent variable is a named vector then the names are extracted to create a phase design (e.g., values = c(A = 2,3,5,4,3, B = 6,5,4,3) will create an AB phase design with five and four measuresments). An scdf contains several attributes: dvar The name of the dependent variable. phase The name of the phase variable. mt The name of the measurement time variable. author Information on the author of the data. info Further information on the data. E.g., a publication. dvar, phase, and mt are the defaults most of the scan function use. You can change the values of the attributes with the scdf_attr function (e.g., scdf_attr(exampleAB_add, "dvar") <- "depression" defines depression as the dependent variable. Please notice that all scan functions have arguments to define dvar, phase, and mt for a given analysis.

Value

Returns a single-case data frame scdf suitable for all functions of the scan package. Multiple data sets (e.g. from Multiple Baseline Designs) can be listed.

Author(s)

Juergen Wilbert

Examples

## Scores on a letter naming task were collected on eleven days in a row. The intervention
## started after the fifth measurement, so the first B phase measurement was 6 (B.start = 6).
klaas <- scdf(
  c(5, 7, 8, 5, 7, 12, 16, 18, 15, 14, 19), 
  B.start = 6, name = "Klaas"
)
plot(klaas)

#Alternative coding 1:
klaas <- scdf(
  c(A = 5, 7, 8, 5, 7, B = 12, 16, 18, 15, 14, 19), 
  name = "Klaas"
)

#Alternative coding 2:
klaas <- scdf(
  c(5, 7, 8, 5, 7, 12, 16, 18, 15, 14, 19), 
  phase.design = c(A = 5, B = 6), name = "Klaas"
)

## Unfortunately in a similar SCDR there were no data collected on days 3 and 9. Use NA to
## pass them to the package.
emmi <- scdf(c(5, 7, NA, 5, 7, 12, 16, 18, NA, 14, 19), 
  phase.design = c(A = 5, B = 6), name = "Emmi")
describeSC(emmi)

## In a MBD over three persons, data were again collected eleven days in a row. Intervention
## starting points differ between subjects as they were randomly assigned. The three SCDFs
## are then combined in a list for further conjoined analyses.
charlotte <- scdf(c(A = 5, 7, 10, 5, 12, B = 7, 10, 18, 15, 14, 19))
theresa   <- scdf(c(A = 3, 4, 3, 5, B = 7, 4, 7, 9, 8, 10, 12))
antonia   <- scdf(c(A = 9, 8, 8, 7, 5, 7, B = 6, 14, 15, 12, 16))
mbd <- c(charlotte, theresa, antonia)
names(mbd) <- c("Charlotte", "Theresa", "Antonia")
overlapSC(mbd)

## In a classroom-based intervention it was not possible to measure outcomes every day, but
## only on schooldays. The sequence of measurements is passed to the package by using a
## vector of measurement times.
frida <- scdf(
  c(A = 3, 2, 4, 2, 2, 3, 5, 6, B = 8, 10, 8, 12, 14, 13, 12),
  mt = c(1, 2, 3, 4, 5, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18)
)
summary(frida)
plot(frida)
describeSC(frida)

## example with two independent variables and four phases
jim  <- scdf(
  zvt = c(47, 58, 76, 63, 71, 59, 64, 69, 72, 77, 76, 73), 
  d2 = c(131, 134, 141, 141, 140, 140, 138, 140, 141, 140, 138, 140), 
  phase.design = c(A1 = 3, B1 = 3, A2 = 3, B2 = 3), dvar = "zvt")
overlapSC(jim, phases = list(c("A1", "A2"), c("B1", "B2")))

scan documentation built on Feb. 12, 2021, 3:01 a.m.