115 compare cor statistic not z score

.gitignore

@@ -19,3 +19,4 @@ cran-comments.md
 Rplots.pdf
 references/working/
 .claude/
+.claude/settings.local.json

NAMESPACE

@@ -134,6 +134,7 @@ importFrom(stats,qlogis)
 importFrom(stats,qnorm)
 importFrom(stats,qt)
 importFrom(stats,quantile)
+importFrom(stats,runif)
 importFrom(stats,sd)
 importFrom(stats,setNames)
 importFrom(stats,t.test)

R/boot_ses_test.R

@@ -177,6 +177,7 @@
 #'   bootstrap confidence intervals, [brunner_munzel()] with
 #'   `test_method = "perm"` for robust TOST on the probability scale.
 #' @name boot_ses_test
+#' @importFrom stats runif
 #' @export boot_ses_test
 
 boot_ses_test <- function(x, ...,

R/compare_cor.R

@@ -39,13 +39,19 @@
 #' * For minimal effect testing ("minimal.effect"), it determines whether the difference falls
 #'   outside the specified bounds.
 #'
+#' **Note on Fisher's z transformation of bounds:** When `method = "fisher"`, the `null` values
+#' (equivalence bounds) are specified on the **correlation scale** and are internally converted to
+#' the Fisher z scale via `atanh()`. For example, `null = 0.4` is treated as r = 0.4, which maps
+#' to z = 0.4236. If you want bounds expressed directly in Fisher-z units, you should back-transform
+#' them to the correlation scale first using `tanh()` before passing them to this function.
+#'
 #' When performing equivalence or minimal effect testing:
 #' * If a single value is provided for `null`, symmetric bounds ±value will be used
 #' * If two values are provided for `null`, they will be used as the lower and upper bounds
 #'
 #' @return A list with class "htest" containing the following components:
 #'
-#' * **statistic**: z-score with name "z"
+#' * **statistic**: standardized z-score (i.e., the test statistic divided by its standard error) with name "z"
 #' * **p.value**: numeric scalar containing the p-value for the test under the null hypothesis
 #' * **estimate**: difference in correlation coefficients between studies
 #' * **null.value**: the specified hypothesized value(s) for the null hypothesis
@@ -138,10 +144,10 @@ compare_cor = function(r1,
         phi = p_from_z(zhi/z_se, alternative = 'less')
         if(phi >= plo){
           pval = phi
-          z = zhi
+          z = zhi / z_se
         } else {
           pval = plo
-          z = zlo
+          z = zlo / z_se
         }
       }
       if(alternative == "minimal.effect"){
@@ -151,10 +157,10 @@ compare_cor = function(r1,
         phi = p_from_z(zhi/z_se, alternative = 'greater')
         if(phi <= plo){
           pval = phi
-          z = zhi
+          z = zhi / z_se
         } else {
           pval = plo
-          z = zlo
+          z = zlo / z_se
         }
       }
     } else {
@@ -178,10 +184,10 @@ compare_cor = function(r1,
         phi = p_from_z(zhi/se, alternative = 'less')
         if(phi >= plo){
           pval = phi
-          z = zhi
+          z = zhi / se
         } else {
           pval = plo
-          z = zlo
+          z = zlo / se
         }
       }
       if(alternative == "minimal.effect"){
@@ -191,10 +197,10 @@ compare_cor = function(r1,
         phi = p_from_z(zhi/se, alternative = 'greater')
         if(phi <= plo){
           pval = phi
-          z = zhi
+          z = zhi / se
         } else {
           pval = plo
-          z = zlo
+          z = zlo / se
         }
       }
     } else{

tests/testthat/test-corr.R

@@ -388,6 +388,29 @@ test_that("Run examples for boot_cor_test", {
 
 })
 
+test_that("compare_cor: z-statistic is standardized (issue #115)", {
+  result <- compare_cor(
+    r1 = 0.6, df1 = 18,
+    r2 = 0.8, df2 = 23,
+    null = 0.4,
+    method = "fisher",
+    alternative = "equivalence"
+  )
+
+  # Manually compute the expected standardized z
+  z1   <- atanh(0.6)
+  z2   <- atanh(0.8)
+  diff <- z1 - z2
+  SE   <- sqrt(1/17 + 1/22)
+  bound_z <- atanh(0.4)
+
+  expected_z <- (diff - (-bound_z)) / SE
+  expected_p <- 1 - pnorm(expected_z)
+
+  expect_equal(unname(result$statistic), expected_z, tolerance = 1e-6)
+  expect_equal(result$p.value, expected_p, tolerance = 1e-6)
+})
+
 test_that("Run examples for boot_compare_cor", {
   skip_on_cran()