Created difficulty matrix generation R script + initial scenarios

Scripts/R/generate_item_difficulties.R

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+###################################################
+# Function: generate_diff_irt
+# Generates item difficulty threshold matrix for
+# IRT model simulation
+###################################################
+
+
+generate_diff_irt <- function(J=7,M=4) {
+  # if J=7, item 5. Else, item 3
+  if(J==7){
+    i <- 5
+  }
+  if(J==4){
+    i <- 3
+  }
+  difficulties = matrix(c(0), J,M-1)
+  rownames(difficulties)=paste("item",1:J)
+  colnames(difficulties)=paste("Moda", 1:(M-1))
+  for (j in 1:J){
+    difficulties[j,1] = qnorm(j/(J+1))
+  }
+  for (j in 1:J){
+    for (m in 2:(M-1)){
+      difficulties[j,m]= difficulties[j,1]+(m-1)*2/(M-2)
+    }
+  }
+  difficulties = difficulties-mean(difficulties)
+  return(difficulties)
+}
+
+
+
+
+
+###################################################
+# GENERATE MATRIX FOR SIMULATION
+###################################################
+
+

Scripts/Scenarios/NoDIF/scenarios_noDIF_baseline.do

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+*=================================================================================================================================================
+* Date : 2024-01-04
+* Stata version : Stata 18 SE
+*
+* This program creates dataset without DIF for a randomized controlled trial scenario
+*
+* ado-files needed : - simirt (version 4.3 August 29, 2019, available on OSF)
+*
+* outputs : TBA
+*
+*
+* Warning : To obtain reproduce the data obtained in the .csv files in this repository, use 'simirt_setseed.ado' instead of 'simirt.ado'
+*
+*
+*================================================================================================================================================
+
+* Load simirt.ado
+adopath+"/home/corentin/Documents/These/Recherche/Simulations/Modules/simirt.ado"
+
+* Set data output folder path
+local path = "/home/corentin/Documents/These/Recherche/Simulations/Data"
+
+
+
+* Scenarios with : n = 800
+*==========================
+
+* Scenario No. 7 : J = 4 items + C1 et C2 not correlated
+
+forvalues replication = 1/500 {
+		di "replication = `replication'"
+		mat D= (-1.84,-0.84,0.16 \ -1.25,-0.25,0.75\-0.75,0.25,1.25 \-0.16,0.84,1.84)
+		qui simirt, nbobs(200) mu(0) cov(1) dim(4) pcm(D) clear
+		qui gen C1 = 0
+		qui gen C2 = 0
+		tempfile grp00
+		qui save `grp00',replace
+
+		mat D= (-1.84,-0.84,0.16 \ -1.25,-0.25,0.75\-0.75,0.25,1.25 \-0.16,0.84,1.84)
+		qui simirt, nbobs(200) mu(0) cov(1) dim(4) pcm(D) clear
+		qui gen C1 = 1
+		qui gen C2 = 0
+		tempfile grp10
+		qui save `grp10',replace
+
+		mat D= (-1.84,-0.84,0.16 \ -1.25,-0.25,0.75\-0.75,0.25,1.25 \-0.16,0.84,1.84)
+		qui simirt, nbobs(200) mu(0) cov(1) dim(4) pcm(D) clear
+		qui gen C1 = 0
+		qui gen C2 = 1
+		tempfile grp01
+		qui save `grp01',replace
+
+		mat D= (-1.84,-0.84,0.16 \ -1.25,-0.25,0.75\-0.75,0.25,1.25 \-0.16,0.84,1.84)
+		qui simirt, nbobs(200) mu(0) cov(1) dim(4) pcm(D) clear
+		qui gen C1 = 1
+		qui gen C2 = 1
+		tempfile grp11
+		qui save `grp11',replace
+
+		clear
+		use `grp00'
+		qui append using `grp10'
+		qui append using `grp01'
+		qui append using `grp11'
+		drop id
+		qui gen id = _n
+		order(id)
+		qui gen replication = `replication'
+		if `replication'==1{
+			tempfile data
+			qui save `data'
+		}
+		else{
+			qui append using `data'
+			qui save `data',replace
+		}
+	}
+	export delimited using "`path'\Scenario7.csv", replace