diff --git a/src/stv/mod.rs b/src/stv/mod.rs
index f2916aa..dc951c8 100644
--- a/src/stv/mod.rs
+++ b/src/stv/mod.rs
@@ -266,6 +266,10 @@ impl STVOptions {
 				return Err(STVError::InvalidOptions("--subtract-nontransferable requires --transferable-only"));
 			}
 		}
+		if !self.immediate_elect && self.surplus_order != SurplusOrder::BySize {
+			// Invalid because there is no other metric to determine which surplus to distribute
+			return Err(STVError::InvalidOptions("--no-immediate-elect requires --surplus-order by_size"));
+		}
 		if self.min_threshold != "0" && self.defer_surpluses {
 			// TODO: NYI
 			return Err(STVError::InvalidOptions("--min-threshold is incompatible with --defer-surpluses (not yet implemented)"));