New "sign up" stat in the chapter admin area

app/components/admin/dashboard/health_card_component.html.erb

@@ -1,6 +1,6 @@
 <div class="card border-info mb-4">
   <div class="card-body">
-    <h3>Chapter Health</h3>
+    <h3 class="mb-4">Chapter Health</h3>
     <div class="row">
       <% tiles.each do |tile| %>
         <div class="col-6 col-md-3 text-center mb-2">
@@ -19,6 +19,32 @@
       <div class="col-12">
         <%= content %>
       </div>
+      <div class="col-12 mt-4">
+        <strong class="small mb-2 d-block">New sign-ups (last 3 months)</strong>
+        <table class="table table-sm align-middle mb-0">
+          <thead>
+            <tr>
+              <th scope="col" class="small fw-normal text-muted">Month</th>
+              <th scope="col" class="small fw-normal text-muted text-end">Students</th>
+              <th scope="col" class="small fw-normal text-muted text-end">Coaches</th>
+            </tr>
+          </thead>
+          <tbody>
+            <% new_sign_ups.each do |row| %>
+              <tr>
+                <th scope="row" class="fw-normal"><%= sign_up_month_label(row[:month]) %></th>
+                <td class="text-end"><%= number_value(row[:students]) %></td>
+                <td class="text-end"><%= number_value(row[:coaches]) %></td>
+              </tr>
+            <% end %>
+            <tr class="fw-bold">
+              <th scope="row">Total</th>
+              <td class="text-end"><%= number_value(sign_up_totals[:students]) %></td>
+              <td class="text-end"><%= number_value(sign_up_totals[:coaches]) %></td>
+            </tr>
+          </tbody>
+        </table>
+      </div>
     </div>
   </div>
 </div>

app/components/admin/dashboard/health_card_component.rb

@@ -9,13 +9,14 @@ class HealthCardComponent < ViewComponent::Base
       BUCKET_CLASSES = { inactive: 'bg-secondary', dormant: 'bg-warning text-dark',
                          active: 'bg-success' }.freeze
 
-      def initialize(health:) # rubocop:disable Lint/MissingSuper
+      def initialize(health:, new_sign_ups: []) # rubocop:disable Lint/MissingSuper
         @health = health
+        @new_sign_ups = new_sign_ups
       end
 
       private
 
-      attr_reader :health
+      attr_reader :health, :new_sign_ups
 
       def bucket_badge_class = BUCKET_CLASSES.fetch(health.bucket)
 
@@ -54,6 +55,15 @@ def eligible_members_value
         number_value(health.eligible_students + health.eligible_coaches)
       end
 
+      def sign_up_month_label(month)
+        month.strftime('%b %Y')
+      end
+
+      def sign_up_totals
+        { students: new_sign_ups.sum { |row| row[:students] },
+          coaches: new_sign_ups.sum { |row| row[:coaches] } }
+      end
+
       def number_value(value)
         number_with_delimiter(value)
       end

app/controllers/admin/chapters_controller.rb

@@ -34,6 +34,7 @@ def show
     @groups = @chapter.groups
     @subscribers = @chapter.subscriptions.kept.last(20).reverse
     @how_you_found_us = HowYouFoundUsPresenter.new(@chapter)
+    @new_sign_ups = new_sign_ups(@chapter)
   end
 
   def edit
@@ -117,6 +118,33 @@ def set_chapter
     @chapter = Chapter.find(params[:id])
   end
 
+  def new_sign_ups(chapter)
+    months = new_sign_up_months
+    counts = sign_up_counts(chapter, months)
+    months.map do |month|
+      { month: month.to_date,
+        students: counts.fetch([month.to_date, 'Students'], 0),
+        coaches: counts.fetch([month.to_date, 'Coaches'], 0) }
+    end
+  end
+
+  def sign_up_counts(chapter, months)
+    chapter.subscriptions
+           .where(created_at: months.first.beginning_of_day..)
+           .joins(:group)
+           .group(month_bucket, 'groups.name')
+           .pluck(month_bucket, 'groups.name', Arel.sql('COUNT(*)'))
+           .to_h { |month, name, count| [[month, name], count] }
+  end
+
+  def new_sign_up_months
+    [2.months.ago, 1.month.ago, Time.current].map(&:beginning_of_month)
+  end
+
+  def month_bucket
+    Arel.sql("DATE_TRUNC('month', subscriptions.created_at AT TIME ZONE '#{Time.zone.tzinfo.identifier}')::date")
+  end
+
   def member_emails(chapter, type)
     members =
       case type

app/views/admin/chapters/show.html.haml

@@ -58,7 +58,7 @@
             %div.text-muted.small= "Based on #{pluralize(@how_you_found_us.total_responses, 'response')}"
 
     .col-12.col-lg-8
-      = render Admin::Dashboard::HealthCardComponent.new(health: @chapter_health) do
+      = render Admin::Dashboard::HealthCardComponent.new(health: @chapter_health, new_sign_ups: @new_sign_ups) do
         = render Admin::Dashboard::WorkshopTimelineComponent.new(past: @past_workshop_dates, future: @planned_workshop_dates, event_past: @past_event_dates, event_future: @planned_event_dates)
       .mb-4.mt-md-4.mt-lg-0
         .d-md-flex.justify-content-between.align-items-center

spec/components/admin/dashboard/health_card_component_spec.rb

@@ -38,6 +38,24 @@
     expect(page).to have_css('.badge', text: 'inactive')
   end
 
+  it 'renders new sign-ups split across the last 3 months' do
+    health = Admin::Dashboard::ChapterHealth.row(chapter:)
+    sign_ups = [
+      { month: Date.new(2026, 9, 1), students: 5, coaches: 3 },
+      { month: Date.new(2026, 10, 1), students: 8, coaches: 4 },
+      { month: Date.new(2026, 11, 1), students: 2, coaches: 1 }
+    ]
+
+    render_inline(described_class.new(health:, new_sign_ups: sign_ups))
+
+    expect(page).to have_text('New sign-ups (last 3 months)')
+    expect(page).to have_css('th', text: 'Sep 2026')
+    expect(page).to have_css('th', text: 'Oct 2026')
+    expect(page).to have_css('th', text: 'Nov 2026')
+    expect(page).to have_css('tr', text: /Sep 2026\s+5\s+3/)
+    expect(page).to have_css('tr.fw-bold', text: /Total\s+15\s+8/)
+  end
+
   it 'renders the yielded content inside the card' do
     health = Admin::Dashboard::ChapterHealth.row(chapter:)
 

spec/controllers/admin/chapters_controller_spec.rb

@@ -125,5 +125,28 @@
       expect(response).to be_successful
       expect(response.body).to include('Chapter Health')
     end
+
+    it 'shows new sign-ups split across the last 3 months' do
+      travel_to(Time.zone.local(2026, 11, 6, 12, 0)) do
+        login_as_admin(Fabricate(:member))
+        chapter = Fabricate(:chapter)
+        students = Fabricate(:group, name: 'Students', chapter:)
+        coaches = Fabricate(:group, name: 'Coaches', chapter:)
+        Fabricate(:subscription, group: students, created_at: Time.zone.local(2026, 9, 10))
+        Fabricate(:subscription, group: coaches, created_at: Time.zone.local(2026, 10, 10))
+        Fabricate(:subscription, group: students, created_at: Time.zone.local(2026, 11, 2))
+        Fabricate(:subscription, group: students, created_at: Time.zone.local(2026, 8, 20))
+
+        get :show, params: { id: chapter.id }
+
+        expect(response.body).to include('New sign-ups (last 3 months)')
+        expected = [
+          { month: Date.new(2026, 9, 1), students: 1, coaches: 0 },
+          { month: Date.new(2026, 10, 1), students: 0, coaches: 1 },
+          { month: Date.new(2026, 11, 1), students: 1, coaches: 0 }
+        ]
+        expect(controller.view_assigns['new_sign_ups']).to eq(expected)
+      end
+    end
   end
 end