estimate_valid: Estimate the nomination validity of an identification system...

In mcbeem/giftedCalcs: Psychometrics for Gifted Program Identification

Estimate the nomination validity of an identification system given x of the identified students

Description

estimate_valid estimates the nomination validity of an identification system given the observed scores of the identified students, the confirmatory test cutoff, the nomination cutoff, and the proportion of students that are identified. The test cutoff, if not known, is inferred from the minimum score. The nomination cutoff is inferred from the proportion of students who are nominated under the assumption that the nomination x follow a standard normal distribution.

Usage

estimate_valid(x, nom.rate, id.rate, pop.mean = 0, pop.sd = 1, adjust = 1)

Arguments

x	Numeric vector of observed scores.
nom.rate	The proportion of students who have been nominated. Range (0, 1). Used to calculate the nomination cutoff.
id.rate	The proportion of students who have been identified. Range (0, 1). Must be less than or equal to nom.rate.
pop.mean	The known general population mean of the x. Defaults to 0.
pop.sd	The known general population standard deviation of the x. Defaults to 1.
adjust	Controls the bandwidth of the density estimator. Defaults to 1.0, which has been found to perform well in simulation.

Details

The function uses the Levenburg-Marquardt algorithm to minimize the discrepancy between the density of the x and the theoretical unnormalized density of the data. See d_identified for details.

Examples

# generate some observed scores
# (note the lack of a relyt argument)
# true validity is .6
set.seed(1)
x <- r_identified(
  n = 500, test.cutoff = .9, valid = .6,
  nom.cutoff = .85
)

# calculate the identification rate implied by the system parameters
id.rate <- marginal_psychometrics(
  test.cutoff = .9, valid = .6,
  nom.cutoff = .85
)$identification.rate

# calculate the nomination rate implied by the system parameters
nom.rate <- marginal_psychometrics(
  test.cutoff = .9, valid = .6,
  nom.cutoff = .85
)$nom.rate

# estimate the system parameters from the data
estimate_valid(x = x, id.rate = id.rate, nom.rate = nom.rate)

mcbeem/giftedCalcs documentation built on May 3, 2022, 3:34 a.m.