diff --git a/NAMESPACE b/NAMESPACE
index 07e6720..5399c4f 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -63,7 +63,7 @@ export(pull_outcome)
 export(pull_panel_time)
 export(pull_panel_unit)
 export(pull_treatment)
-export(set_causal_col)
+export(set_causal_cols)
 export(set_outcome)
 export(set_panel)
 export(set_treatment)
diff --git a/R/causal_cols.R b/R/causal_cols.R
index cf26683..3503a1f 100644
--- a/R/causal_cols.R
+++ b/R/causal_cols.R
@@ -6,7 +6,7 @@
 #' @param data A [causal_tbl].
 #' @param value New value for `causal_cols`.
 #' @param ... Named attributes to add to `data`'s causal attributes.
-#' @param what The causal column to get or set.
+#' @param what The causal column to get or add.
 #' @param ptype A type to coerce a single added column to.
 #'
 #' @returns Varies. Setter methods return the original `data`, perhaps invisibly.
@@ -16,9 +16,10 @@
 #'   milk_first = c(0, 1, 0, 1, 1, 0, 0, 1),
 #'   guess = c(0, 1, 0, 1, 1, 0, 0, 1)
 #' ) |>
-#'   set_causal_col("treatment", guess=milk_first)
+#'   set_causal_cols(outcomes=guess, treatments=c(guess=milk_first))
 #' print(data)
-#' get_causal_col(data, "treatment")
+#' get_causal_col(data, "treatments")
+#' get_causal_col(data, "outcomes")
 #' causal_cols(data)
 #' @export
 causal_cols <- function(data) {
@@ -33,11 +34,14 @@ causal_cols <- function(data) {
 
 #' @describeIn causal_cols Set column(s) for a `causal_col`
 #' @export
-set_causal_col <- function(data, what, ...) {
+set_causal_cols <- function(data, ...) {
     data <- as_causal_tbl(data)
-    dots <- rlang::quo(c(...))
-    cols <- multi_col_name(dots, data, what)
-    causal_cols(data)[[what]] <- cols
+    dots <- rlang::enquos(...)
+    for (i in seq_along(dots)) {
+        what <- names(dots)[i]
+        cols <- multi_col_name(dots[[i]], data, what)
+        causal_cols(data)[[what]] <- cols
+    }
     data
 }
 #' @describeIn causal_cols Add a single column to a `causal_col`
@@ -47,7 +51,7 @@ add_causal_col <- function(data, what, ..., ptype=NULL) {
     dots <- enquos(...)
     if (length(dots) > 1) {
         cli_abort(c("Only one column can be added at a time.",
-                    ">"="Use {.fn set_causal_col} to add more than one column."),
+                    ">"="Use {.fn set_causal_cols} to add more than one column."),
                   call=parent.frame())
     }
 
diff --git a/man/causal_cols.Rd b/man/causal_cols.Rd
index 802e3d2..af19c5d 100644
--- a/man/causal_cols.Rd
+++ b/man/causal_cols.Rd
@@ -3,7 +3,7 @@
 \name{causal_cols}
 \alias{causal_cols}
 \alias{causal_cols<-}
-\alias{set_causal_col}
+\alias{set_causal_cols}
 \alias{add_causal_col}
 \alias{get_causal_col}
 \title{Work directly with \code{causal_cols}}
@@ -12,7 +12,7 @@ causal_cols(data)
 
 causal_cols(data) <- value
 
-set_causal_col(data, what, ...)
+set_causal_cols(data, ...)
 
 add_causal_col(data, what, ..., ptype = NULL)
 
@@ -23,10 +23,10 @@ get_causal_col(data, what)
 
 \item{value}{New value for \code{causal_cols}.}
 
-\item{what}{The causal column to get or set.}
-
 \item{...}{Named attributes to add to \code{data}'s causal attributes.}
 
+\item{what}{The causal column to get or add.}
+
 \item{ptype}{A type to coerce a single added column to.}
 }
 \value{
@@ -40,7 +40,7 @@ functionality.
 \itemize{
 \item \code{causal_cols(data) <- value}: Set \code{causal_cols}
 
-\item \code{set_causal_col()}: Set column(s) for a \code{causal_col}
+\item \code{set_causal_cols()}: Set column(s) for a \code{causal_col}
 
 \item \code{add_causal_col()}: Add a single column to a \code{causal_col}
 
@@ -52,8 +52,9 @@ data <- data.frame(
   milk_first = c(0, 1, 0, 1, 1, 0, 0, 1),
   guess = c(0, 1, 0, 1, 1, 0, 0, 1)
 ) |>
-  set_causal_col("treatment", guess=milk_first)
+  set_causal_cols(outcomes=guess, treatments=c(guess=milk_first))
 print(data)
-get_causal_col(data, "treatment")
+get_causal_col(data, "treatments")
+get_causal_col(data, "outcomes")
 causal_cols(data)
 }
diff --git a/tests/testthat/test-causal_cols.R b/tests/testthat/test-causal_cols.R
index c7f6fed..cb16080 100644
--- a/tests/testthat/test-causal_cols.R
+++ b/tests/testthat/test-causal_cols.R
@@ -91,7 +91,7 @@ test_that("lower-level getting and setting", {
         y = c(1, 3, 2, 3, 2, 4, 4, 5)
     )
 
-    x2 <- set_causal_col(x, "treatments", y=trt, id=year)
+    x2 <- set_causal_cols(x, treatments=c(y=trt, id=year))
     expect_equal(get_treatment(x2), c(y="trt"))
     expect_length(causal_cols(x2)$treatments, 2)
 
@@ -100,10 +100,10 @@ test_that("lower-level getting and setting", {
     expect_length(causal_cols(x3)$treatments, 1)
     expect_error(add_causal_col(x, "treatments", y=trt, y2=trt2), "more than one")
 
-    x3 <- set_causal_col(x3, "treatments", id=year)
+    x3 <- set_causal_cols(x3, treatments=c(id=year))
     expect_equal(get_treatment(x3), c(id="year"))
     expect_length(causal_cols(x3)$treatments, 1)
-    expect_error(set_causal_col(x3, "treatments"), "Must select")
+    expect_error(set_causal_cols(x3, treatments=NULL), "Must select")
 
     x4 <- add_causal_col(x, "pscore", trt=id, ptype=factor())
     expect_type(causal_cols(x4)$pscore, "character")
diff --git a/tests/testthat/test-causal_tbl.R b/tests/testthat/test-causal_tbl.R
index 8bab351..3276019 100644
--- a/tests/testthat/test-causal_tbl.R
+++ b/tests/testthat/test-causal_tbl.R
@@ -84,10 +84,16 @@ test_that("causal_tbl slicing and renaming", {
     x_df = as.data.frame(x)
     expect_equal(x[1:2, ], causal_tbl(x_df[1:2, ], .outcome=y, .treatment=trt))
 
+    expect_identical(x, x[])
+
+    y <- x[1:4, ]
+    expect_equal(get_treatment(y), c(y="trt"))
+    expect_equal(get_outcome(y), "y")
+
     y <- x[2]
     expect_null(get_treatment(y))
     expect_equal(get_outcome(y), "y")
-    y <- x[1]
+    y <- x[, 1]
     expect_null(get_outcome(y))
     expect_equal(get_treatment(y), "trt") # no y= !