| var_lnd {r4lineups} | R Documentation |
Variance of ln of diagnosticity ratio
Description
Function to compute variance of ln(d) for k lineup pairs
Usage
var_lnd(linedf)
Arguments
linedf |
A dataframe of parameters for computing diagnosticity ratio |
Details
To get linedf, use the diag_param helper function
diag_param returns a dataframe containing the following:
-
n11: Number of mock witnesses who identified the suspect in the target present condition
-
n21: Number of mock witnesses who did not identify the suspect in the target present condition
-
n12: Number of mock witnesses who identified the suspect in the target absent condition
-
n13: Number of mock witnesses who did not identify the suspect in the target absent condition
Value
A dataframe containing ln of the variance of the diagnosticity ratio for each lineup.
References
Malpass, R. S. (1981). Effective size and defendant bias in eyewitness identification lineups. Law and Human Behavior, 5(4), 299-309.
Malpass, R. S., Tredoux, C., & McQuiston-Surrett, D. (2007). Lineup construction and lineup fairness. In R. Lindsay, D. F. Ross, J. D. Read, & M. P. Toglia (Eds.), Handbook of Eyewitness Psychology, Vol. 2: Memory for people (pp. 155-178). Mahwah, NJ: Lawrence Erlbaum Associates.
Tredoux, C. G. (1998). Statistical inference on measures of lineup fairness. Law and Human Behavior, 22(2), 217-237.
Tredoux, C. (1999). Statistical considerations when determining measures of lineup size and lineup bias. Applied Cognitive Psychology, 13, S9-S26.
Wells, G. L.,Leippe, M. R., & Ostrom, T. M. (1979). Guidelines for empirically assessing the fairness of a lineup. Law and Human Behavior, 3(4), 285-293.
Examples
#Target present data:
A <- round(runif(100,1,6))
B <- round(runif(70,1,5))
C <- round(runif(20,1,4))
lineup_pres_list <- list(A, B, C)
rm(A, B, C)
#Target absent data:
A <- round(runif(100,1,6))
B <- round(runif(70,1,5))
C <- round(runif(20,1,4))
lineup_abs_list <- list(A, B, C)
rm(A, B, C)
#Pos list
lineup1_pos <- c(1, 2, 3, 4, 5, 6)
lineup2_pos <- c(1, 2, 3, 4, 5)
lineup3_pos <- c(1, 2, 3, 4)
pos_list <- list(lineup1_pos, lineup2_pos, lineup3_pos)
rm(lineup1_pos, lineup2_pos, lineup3_pos)
#Nominal size:
k <- c(6, 5, 4)
#Use diag param helper function to get data (n11, n21, n12, n22):
linedf <- diag_param(lineup_pres_list, lineup_abs_list, pos_list, k)
#Call:
var <- var_lnd(linedf)