diff --git a/DESCRIPTION b/DESCRIPTION
index 624c22b5..ccf972e5 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: multinma
 Title: Bayesian Network Meta-Analysis of Individual and Aggregate Data
-Version: 0.7.1.9001
+Version: 0.7.1.9002
 Authors@R: 
     person(given = c("David", "M."),
            family = "Phillippo",
diff --git a/NEWS.md b/NEWS.md
index 14a21e76..f3d27238 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -3,6 +3,8 @@
 * Fix: Predictions for non-proportional hazards IPD NMA or ML-NMR survival 
 models using `aux_regression = ~.trt` were incorrectly omitting the treatment 
 effects on the auxiliary parameter(s) in some cases (#43).
+* Fix: Calling `marginal_effects()` for survival outcomes with a single target
+population previously gave an error.
 
 # multinma 0.7.1
 
diff --git a/R/marginal_effects.R b/R/marginal_effects.R
index 2f1b0452..d799e037 100644
--- a/R/marginal_effects.R
+++ b/R/marginal_effects.R
@@ -207,7 +207,7 @@ marginal_effects <- function(object,
   vars <- intersect(c(".study", ".time", ".quantile", ".category"), colnames(pred_meta))
 
   if (".time" %in% vars) {
-    pred_meta <- dplyr::group_by(pred_meta, .data$.study, .data$.trt) %>%
+    pred_meta <- { if (".study" %in% vars) dplyr::group_by(pred_meta, .data$.study, .data$.trt) else dplyr::group_by(pred_meta, .data$.trt) } %>%
       dplyr::mutate(.time_id = 1:dplyr::n()) %>%
       dplyr::ungroup()