raw2scaled {test2norm}

Convert raw neuropsychological test scores to scaled scores.

Description

Convert raw neuropsychological test scores to scaled scores.

Usage

raw2scaled(
  data = NULL,
  test = NULL,
  test.min = NULL,
  test.max = NULL,
  test.better = c("High", "Low"),
  group.id = NULL,
  control.id = NULL,
  all.controls = FALSE,
  rnd.s = TRUE
)

Arguments

data

a data frame containing the test score

test

a character string specifying the name of the variable containing the test score

test.min

a real number indicating the smallest possible test score

test.max

a real number indicating the largest possible test score

test.better

a character string indicating direction of the scores. Use "High" if high test scores imply better performance, use "Low" otherwise.

group.id

a character string specifying the name of the variable containing group identification (i.e. control vs exposed/test/risk). Ignored, if all.controls = TRUE.

control.id

a character string specifying the label of the control group within group.id variable. Ignored, if all.controls = TRUE.

all.controls

a logical indicating whether all observations should be treated as controls. Overwrites group.id and control.id.

rnd.s

a logical indicating whether the scaled scores should be rounded. Default is TRUE.

Details

The raw2scaled() function can be used by neuropsychologists, who wish to convert raw test scores to scaled scores (mean=10, SD=3), using methods described in Heaton et al. (2003 & 2009). The raw test scores that have many decimal digits should be rounded to fewer digits prior to the application of the raw2scaled() function. This will significantly reduce software running time. The recommended number of decimal digits is 4 or fewer. Values below test.min or above test.max will result in NA. Detailed description of the procedure are found in Umlauf et al. (2024).

Note that the function does not guarantee that the calculated scaled scores range from 0 to 20, because it uses normal distribution quantiles. Therefore, scaled scores outside 0-20 range are possible.

Value

A list consisting of 3 objects. The first two are vectors containing the original raw test scores and the calculated scaled scores. The third object in the list, called SS.maps, contains conversions from raw scores to scaled scores in a form of a table with two columns, one representing scaled scores (one per row) and one representing raw scores (a single value or range of raw values corresponding to each scaled score). Note that this table shows rounded scaled scores regardless of the value for rnd.s.

Author(s)

Anya Umlauf

References

Umlauf A et al. (2024) Automated procedure for demographic adjustments on cognitive test scores. <doi:10.1080/23279095.2023.2288231>

Heaton RK, Taylor MJ, & Manly J (2003) Demographic effects and use of demographically corrected norms with the WAIS-III and WMS-III. In: Tulsky D et al. (Eds.) Clinical Interpretation of the WAIS-III and WMS-III. San Diego, CA: Academic Press, 183-210.

Heaton RK, Ryan L, & Grant I (2009) Demographic influences and use of demographically corrected norms in neuropsychological assessment. In Grant I & Adams KM (Eds.) Neuropsychological Assessment of Neuropsychiatric and Neuromedical Disorders. New York, NY: Oxford University Press, 127-155.

Examples

data(PsychTestData)
raw2scaled(data = PsychTestData, test = "rawscore",
           test.min = 0, test.max = 36, test.better = "High",
           group.id = "group", control.id = "control")