diff --git a/app/models/category.rb b/app/models/category.rb
index d180a34eb6a..b0e67c869cf 100644
--- a/app/models/category.rb
+++ b/app/models/category.rb
@@ -17,7 +17,6 @@ class Category < ActiveRecord::Base
   after_save :invalidate_site_cache
   after_destroy :invalidate_site_cache
 
-
   def uncategorized_validator
     return errors.add(:name, I18n.t(:is_reserved)) if name == SiteSetting.uncategorized_name
     return errors.add(:slug, I18n.t(:is_reserved)) if slug == SiteSetting.uncategorized_name
@@ -26,24 +25,22 @@ class Category < ActiveRecord::Base
   def self.popular
     order('topic_count desc')
   end
-
+  
+  # Recalculates `topics_year`, `topics_month`, and `topics_week`
+  # for each Category.
   def self.update_stats
-    exec_sql "UPDATE categories
-              SET topics_week = (SELECT COUNT(*)
-                                FROM topics as ft
-                                WHERE ft.category_id = categories.id
-                                  AND ft.created_at > (CURRENT_TIMESTAMP - INTERVAL '1 WEEK')
-                                  AND ft.visible),
-                  topics_month = (SELECT COUNT(*)
-                                FROM topics as ft
-                                WHERE ft.category_id = categories.id
-                                  AND ft.created_at > (CURRENT_TIMESTAMP - INTERVAL '1 MONTH')
-                                  AND ft.visible),
-                  topics_year = (SELECT COUNT(*)
-                                FROM topics as ft
-                                WHERE ft.category_id = categories.id
-                                  AND ft.created_at > (CURRENT_TIMESTAMP - INTERVAL '1 YEAR')
-                                  AND ft.visible)"
+    topics = Topic
+               .select("COUNT(*)")
+               .where("topics.category_id = categories.id")
+               .visible
+
+    topics_year = topics.created_since(1.year.ago).to_sql
+    topics_month = topics.created_since(1.month.ago).to_sql
+    topics_week = topics.created_since(1.week.ago).to_sql
+    
+    Category.update_all("topics_year = (#{topics_year}), 
+                         topics_month = (#{topics_month}), 
+                         topics_week = (#{topics_week})")
   end
 
   # Use the first paragraph of the topic's first post as the excerpt
diff --git a/app/models/topic.rb b/app/models/topic.rb
index 8c26deca3c2..5977f5bd7ed 100644
--- a/app/models/topic.rb
+++ b/app/models/topic.rb
@@ -167,7 +167,11 @@ class Topic < ActiveRecord::Base
   def self.visible
     where(visible: true)
   end
-
+  
+  def self.created_since(time_ago)
+    where("created_at > ?", time_ago)
+  end
+  
   def private_message?
     self.archetype == Archetype.private_message
   end
diff --git a/spec/fabricators/topic_fabricator.rb b/spec/fabricators/topic_fabricator.rb
index 8647b0e17fd..bc4e6074663 100644
--- a/spec/fabricators/topic_fabricator.rb
+++ b/spec/fabricators/topic_fabricator.rb
@@ -3,6 +3,10 @@ Fabricator(:topic) do
   title { sequence(:title) { |i| "Test topic #{i}" } }
 end
 
+Fabricator(:deleted_topic, from: :topic) do
+  deleted_at Time.now 
+end
+
 Fabricator(:topic_allowed_user) do 
 end
 
diff --git a/spec/models/category_spec.rb b/spec/models/category_spec.rb
index 96bf849e427..c796742837a 100644
--- a/spec/models/category_spec.rb
+++ b/spec/models/category_spec.rb
@@ -157,31 +157,57 @@ describe Category do
   end
 
   describe 'update_stats' do
-
-    # We're going to test with one topic. That's enough for stats!
+    
     before do
       @category = Fabricate(:category)
-
-      # Create a non-invisible category to make sure count is 1
-      @topic = Fabricate(:topic, user: @category.user, category: @category)     
-
-      Category.update_stats
-      @category.reload
     end
+    
+    context 'with regular topics' do
 
-    it 'updates topics_week' do
-      @category.topics_week.should == 1
+      before do
+        @category.topics << Fabricate(:topic, 
+                                      user: @category.user)     
+        Category.update_stats
+        @category.reload
+      end
+
+      it 'updates topics_week' do
+        @category.topics_week.should == 1
+      end
+
+      it 'updates topics_month' do
+        @category.topics_month.should == 1
+      end
+
+      it 'updates topics_year' do
+        @category.topics_year.should == 1
+      end
+    
     end
+    
+    context 'with deleted topics' do
 
-    it 'updates topics_month' do
-      @category.topics_month.should == 1
-    end
+      before do
+        @category.topics << Fabricate(:deleted_topic, 
+                                      user: @category.user)
+        Category.update_stats
+        @category.reload
+      end
+
+      it 'does not count deleted topics for topics_week' do
+        @category.topics_week.should == 0
+      end
+
+      it 'does not count deleted topics for topics_month' do
+        @category.topics_month.should == 0
+      end
+
+      it 'does not count deleted topics for topics_year' do
+        @category.topics_year.should == 0
+      end
 
-    it 'updates topics_year' do
-      @category.topics_year.should == 1
     end
 
   end
 
 end
-