adjust_ezdm_accuracy: Adjust Accuracy Counts for Contamination (deprecated)

In bmm: Easy and Accessible Bayesian Measurement Models Using 'brms'

Adjust Accuracy Counts for Contamination (deprecated)

Description

Deprecated. ezdm_summary_stats() now returns contaminant-free n_upper and n_trials, so this second step is no longer needed; applying it corrects the same cell twice. Set the guess rate with the guess_rate argument of ezdm_summary_stats() instead.

Adjusts accuracy counts (n_upper, n_trials) by removing estimated contaminant trials using binomial sampling. Contaminant trials are assumed to produce correct responses at a fixed guess rate (e.g., 0.5 for 2AFC tasks).

Usage

adjust_ezdm_accuracy(n_upper, n_trials, contaminant_prop, guess_rate = 0.5)

Arguments

n_upper	Numeric. Count of upper boundary (correct) responses, a single value.
n_trials	Numeric. Total number of trials, a single value.
contaminant_prop	Numeric. Estimated proportion of contaminant trials (e.g., from the contaminant_prop column of ezdm_summary_stats()), a single value.
guess_rate	Numeric. Assumed accuracy rate for contaminant trials (random guessing). Default is 0.5 (appropriate for 2AFC tasks).

Details

The function adjusts one cell at a time. Vectors of length greater than one are an error; to correct several cells, use ezdm_summary_stats() on each group.

Uses binomial sampling to estimate the number of contaminant trials and contaminant correct responses, then subtracts these from the raw counts. Because of the stochastic sampling, results will vary across calls unless a seed is set by the user.

Value

A 1-row data.frame with columns n_upper_adj and n_trials_adj (integers). When contaminant_prop is NA or <= 0, returns the original counts unchanged.

See Also

ezdm_summary_stats() for computing the summary statistics and contamination proportions

Examples

# Deprecated. ezdm_summary_stats() returns contaminant-free counts already:
set.seed(42)
rt <- c(rnorm(80, 0.55, 0.05), runif(20, 0.1, 4))
response <- c(rbinom(80, 1, 0.85), rbinom(20, 1, 0.5))
ezdm_summary_stats(rt, response, contaminant_bound = c(0.1, 4))

bmm documentation built on Oct. 16, 2026, 9:08 a.m.