Look up norm table values — lookup

Transforms raw values to norm values based on a norm table.

Usage

lookup_norms(
  rawscores,
  group = NULL,
  normtable,
  from = "raw",
  to = "T",
  group_label = names(group)
)

Arguments

rawscores: A vector with raw scores.
group: A vector with group affiliations or a list with vectors for multiple group categorizations.
normtable: An excel file name or a data frame containing a norm table.
from: Label of the raw score variable in file.
to: Label of the norm score variable in file.
group_label: Label of the group variable in file or a list with group labels for multiple group categorizations.

Value

A vector with norm values.

Examples

normtable <- data.frame(
  age = rep(c(6, 8, 6, 8), each = 11),
  gender = rep(c("m", "w"), each = 22),
  raw =  rep(0:10, 4),
  T = rep(c(40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60,
            37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57), 2) + rep(c(0,5), each = 22)
)
rawscores <- c(5,5,3,1)
group_age <- c("6", "8", "6", "8")
group_gender <- c("m", "m", "w", "w")

lookup_norms(rawscores, group = list(age = group_age, gender = group_gender), normtable)
#> [1] 50 47 51 44

## When group values are not specified exactly, raw scores can be ambiguous:
lookup_norms(rawscores, group = list(gender = group_gender), normtable = normtable)
#> Warning: 1: Multiple values found for raw 5 and group m (50, 47). NA returned.
#> 2: Multiple values found for raw 5 and group m (50, 47). NA returned.
#> 3: Multiple values found for raw 3 and group w (51, 48). NA returned.
#> 4: Multiple values found for raw 1 and group w (47, 44). NA returned.
#> [1] NA NA NA NA

lookup_norms(rawscores, normtable = normtable)
#> Warning: 1: Multiple values found for raw 5 (50, 47, 55, 52). NA returned.
#> 2: Multiple values found for raw 5 (50, 47, 55, 52). NA returned.
#> 3: Multiple values found for raw 3 (46, 43, 51, 48). NA returned.
#> 4: Multiple values found for raw 1 (42, 39, 47, 44). NA returned.
#> [1] NA NA NA NA