diff --git a/src-tauri/src/export.rs b/src-tauri/src/export.rs
index 7137ea9..3adc51b 100644
--- a/src-tauri/src/export.rs
+++ b/src-tauri/src/export.rs
@@ -165,7 +165,7 @@ mod tests {
 
     use crate::{
         bounds::WorkloadBounds, config::UserConfig, resident::Resident, schedule::MonthlySchedule,
-        scheduler::Scheduler, slot::Slot,
+        scheduler::Scheduler,
     };
 
     #[fixture]
diff --git a/src-tauri/src/scheduler.rs b/src-tauri/src/scheduler.rs
index 6445ac6..c04fc64 100644
--- a/src-tauri/src/scheduler.rs
+++ b/src-tauri/src/scheduler.rs
@@ -67,15 +67,17 @@ impl Scheduler {
     }
 
     /// Return all valid residents for the current slot
-    pub fn valid_residents(&self, slot: Slot, schedule: &MonthlySchedule) -> Vec<ResidentId> {
-        let other_slot_resident_id = schedule.get_resident_id(&slot.other_position());
+    pub fn valid_residents(&self, slot: Slot, schedule: &MonthlySchedule) -> Vec<&ResidentId> {
+        let required_type = slot.shift_type(); // Calculate once here
+        let other_resident = schedule.get_resident_id(&slot.other_position());
 
         self.config
             .residents
             .iter()
-            .filter(|r| Some(&r.id) != other_slot_resident_id)
+            .filter(|r| Some(&r.id) != other_resident)
             .filter(|r| !r.negative_shifts.contains(&slot.day))
-            .map(|r| r.id.clone())
+            .filter(|r| r.allowed_types.contains(&required_type))
+            .map(|r| &r.id)
             .collect()
     }
 }
diff --git a/src-tauri/src/slot.rs b/src-tauri/src/slot.rs
index 96cde30..f23805e 100644
--- a/src-tauri/src/slot.rs
+++ b/src-tauri/src/slot.rs
@@ -1,6 +1,8 @@
 use chrono::{Datelike, NaiveDate, Weekday};
 use serde::{Deserialize, Serialize};
 
+use crate::schedule::ShiftType;
+
 #[derive(Serialize, Deserialize, PartialEq, PartialOrd, Ord, Eq, Debug, Hash, Clone, Copy)]
 #[serde(rename_all = "camelCase")]
 pub struct Slot {
@@ -88,6 +90,14 @@ impl Slot {
             position: other_pos,
         }
     }
+
+    pub fn shift_type(&self) -> ShiftType {
+        match (self.is_open_shift(), self.position) {
+            (true, ShiftPosition::First) => ShiftType::OpenFirst,
+            (true, ShiftPosition::Second) => ShiftType::OpenSecond,
+            (false, _) => ShiftType::Closed,
+        }
+    }
 }
 
 impl Default for Slot {