diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index e4754e1e..a2da958f 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -714,3 +714,6 @@ Style/TrailingCommaInLiteral:
     - 'Guardfile'
     - 'db/migrate/20140701123203_add_events_per_week_to_conference.rb'
     - 'spec/models/conference_spec.rb'
+
+Style/FrozenStringLiteralComment:
+  Enabled: false
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index f0311c7a..c334cde2 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -154,7 +154,7 @@ module ApplicationHelper
   end
 
   def rescheduling_hint(affected_event_count)
-    if affected_event_count > 0
+    if affected_event_count.positive?
       "You have #{affected_event_count} scheduled #{'event'.pluralize(affected_event_count)}. Changing the conference hours will unschedule those scheduled outside the conference hours."
     end
   end
@@ -196,4 +196,23 @@ module ApplicationHelper
       object.picture.large.url
     end
   end
+
+  def rating_stars(rating, max, options = {})
+    Array.new(max) do |counter|
+      content_tag(
+        'label',
+        '',
+        class: "rating#{' bright' if rating.to_f > counter}",
+        **options
+      )
+    end.join.html_safe
+  end
+
+  def rating_fraction(rating, max, options = {})
+    content_tag(
+      'span',
+      "#{rating}/#{max}",
+      **options
+    )
+  end`
 end
diff --git a/app/helpers/events_helper.rb b/app/helpers/events_helper.rb
index 33694533..6e95ff1d 100644
--- a/app/helpers/events_helper.rb
+++ b/app/helpers/events_helper.rb
@@ -10,17 +10,6 @@ module EventsHelper
     "Registered: #{event.registrations.count}"
   end
 
-  def rating_stars(rating, max, options = {})
-    max.times.collect do |counter|
-      content_tag(
-        'label',
-        '',
-        class: "rating#{' bright' if rating.to_f > counter}",
-        **options
-      )
-    end.join.html_safe
-  end
-
   def replacement_event_notice(event_schedule)
     if event_schedule.present? && event_schedule.replacement?
       replaced_event = (event_schedule.intersecting_event_schedules.withdrawn.first || event_schedule.intersecting_event_schedules.canceled.first).event
@@ -158,10 +147,10 @@ module EventsHelper
       event.id,
       event.send(attribute),
       url:    admin_conference_program_event_path(
-                conference_id,
-                event,
-                event: { attribute => nil }
-              ),
+        conference_id,
+        event,
+        event: { attribute => nil }
+      ),
       method: :patch,
       class:  'switch-checkbox',
       data:   {
@@ -193,13 +182,13 @@ module EventsHelper
         }
       ) do
         content_tag('span', selection) +
-        content_tag('span', '', class: 'caret')
+          content_tag('span', '', class: 'caret')
       end +
-      content_tag('ul', class: 'dropdown-menu') do
-        options.collect do |option|
-          content_tag('li', link_to(option[0], option[1], method: :patch))
-        end.join.html_safe
-      end
+        content_tag('ul', class: 'dropdown-menu') do
+          options.collect do |option|
+            content_tag('li', link_to(option[0], option[1], method: :patch))
+          end.join.html_safe
+        end
     end
   end
 end
diff --git a/app/models/ability.rb b/app/models/ability.rb
index d6b3ef21..c3726f9d 100644
--- a/app/models/ability.rb
+++ b/app/models/ability.rb
@@ -18,7 +18,7 @@ class Ability
     can [:index, :conferences], Organization
     can [:index], Conference
     can [:show], Conference do |conference|
-      conference.splashpage && conference.splashpage.public == true
+      conference&.splashpage&.public
     end
     # Can view the schedule
     can [:schedule, :events], Conference do |conference|
diff --git a/app/models/cfp.rb b/app/models/cfp.rb
index 5105a6bd..02e74abb 100644
--- a/app/models/cfp.rb
+++ b/app/models/cfp.rb
@@ -42,7 +42,7 @@ class Cfp < ApplicationRecord
   def weeks
     result = end_week - start_week + 1
     weeks = Date.new(start_date.year, 12, 31).strftime('%W').to_i
-    result < 0 ? result + weeks : result
+    result.negative? ? result + weeks : result
   end
 
   ##
@@ -63,7 +63,7 @@ class Cfp < ApplicationRecord
 
   def remaining_days(date = Date.today)
     result = (end_date - date).to_i
-    result > 0 ? result : 0
+    result.positive? ? result : 0
   end
 
   ##
@@ -106,12 +106,12 @@ class Cfp < ApplicationRecord
   private
 
   def before_end_of_conference
-    if program && program.conference && program.conference.end_date && end_date && (end_date > program.conference.end_date)
+    if program&.conference && program.conference.end_date && end_date && (end_date > program.conference.end_date)
       errors
       .add(:end_date, "can't be after the conference end date (#{program.conference.end_date})")
     end
 
-    if program && program.conference && program.conference.end_date && start_date && (start_date > program.conference.end_date)
+    if program&.conference && program.conference.end_date && start_date && (start_date > program.conference.end_date)
       errors
       .add(:start_date, "can't be after the conference end date (#{program.conference.end_date})")
     end
diff --git a/app/models/conference.rb b/app/models/conference.rb
index 81e9ec32..f757bfe9 100644
--- a/app/models/conference.rb
+++ b/app/models/conference.rb
@@ -102,7 +102,7 @@ class Conference < ApplicationRecord
   # * +false+ -> If the user is registered
   # * +true+ - If the user isn't registered
   def user_registered? user
-    user.present? && registrations.where(user_id: user.id).count > 0
+    user.present? && registrations.where(user_id: user.id).count.positive?
   end
 
   ##
@@ -113,7 +113,7 @@ class Conference < ApplicationRecord
       event_schedules = program.event_schedules.select do |event_schedule|
         event_schedule.start_time.hour < start_hour ||
         event_schedule.end_time.hour > end_hour ||
-        (event_schedule.end_time.hour == end_hour && event_schedule.end_time.minute > 0)
+        (event_schedule.end_time.hour == end_hour && event_schedule.end_time.minute.positive?)
       end
       event_schedules.each(&:destroy)
     end
@@ -151,7 +151,7 @@ class Conference < ApplicationRecord
   def get_submissions_per_week
     result = []
 
-    if program && program.cfp && program.events
+    if program&.cfp && program.events
       submissions = program.events.select(:week).group(:week).order(:week).count
       start_week = program.cfp.start_week
       weeks = program.cfp.weeks
@@ -168,7 +168,7 @@ class Conference < ApplicationRecord
   #  * +Array+ -> e.g. 'Submitted' => [0, 3, 3, 5]  -> first week 0 events, second week 3 events.
   def get_submissions_data
     result = {}
-    if program && program.cfp && program.events
+    if program&.cfp && program.events
       result = get_events_per_week_by_state
 
       start_week = program.cfp.start_week
@@ -182,7 +182,7 @@ class Conference < ApplicationRecord
           result[state] = pad_array_left_not_kumulative(start_week, values)
         end
       end
-      result['Weeks'] = weeks > 0 ? (1..weeks).to_a : 0
+      result['Weeks'] = weeks.positive? ? (1..weeks).to_a : 0
     end
     result
   end
@@ -256,7 +256,7 @@ class Conference < ApplicationRecord
         result[Ticket.find(ticket).title] = pad_array_left_not_kumulative(start_week, values)
       end
 
-      result['Weeks'] = weeks > 0 ? (1..weeks).to_a : 0
+      result['Weeks'] = weeks.positive? ? (1..weeks).to_a : 0
     end
     result
   end
@@ -269,15 +269,14 @@ class Conference < ApplicationRecord
   def registration_weeks
     result = 0
     weeks = 0
-    if registration_period &&
-        registration_period.start_date &&
+    if registration_period&.start_date &&
         registration_period.end_date
       weeks = Date.new(registration_period.start_date.year, 12, 31)
           .strftime('%W').to_i
 
       result = get_registration_end_week - get_registration_start_week + 1
     end
-    result < 0 ? result + weeks : result
+    result.negative? ? result + weeks : result
   end
 
   ##
@@ -343,7 +342,7 @@ class Conference < ApplicationRecord
       tracks: tracks_set?,
       event_types: event_types_set?,
       difficulty_levels: difficulty_levels_set?,
-      splashpage: splashpage && splashpage.public?
+      splashpage: splashpage&.public?
     }
 
     result.update(
@@ -449,11 +448,11 @@ class Conference < ApplicationRecord
         i += 1
       end
     end
-    if others > 0
+    if others.positive?
       result['Others'] = { 'value' => others, 'color' => next_color(i) }
       i += 1
     end
-    result['None'] = { 'value' => none, 'color' => next_color(i) } if none > 0
+    result['None'] = { 'value' => none, 'color' => next_color(i) } if none.positive?
     result
   end
 
@@ -719,7 +718,7 @@ class Conference < ApplicationRecord
   # * +True+ -> If the registration limit has been reached or exceeded
   # * +False+ -> If the registration limit hasn't been exceeded
   def registration_limit_exceeded?
-    registration_limit > 0 && registrations.count + program.speakers.confirmed.unregistered(program.conference).count >= registration_limit
+    registration_limit.positive? && registrations.count + program.speakers.confirmed.unregistered(program.conference).count >= registration_limit
   end
 
   # Returns an hexadecimal color given a collection. The returned color changed
@@ -757,7 +756,7 @@ class Conference < ApplicationRecord
   # * +True+ -> if accepted booths are equal to the booth limit
   # * +False+ -> Accepted booths have not reached the booth limit
   def maximum_accepted_booths?
-    booth_limit > 0 && booths.accepted.count + booths.confirmed.count >= booth_limit
+    booth_limit.positive? && booths.accepted.count + booths.confirmed.count >= booth_limit
   end
 
   ##
@@ -829,7 +828,7 @@ class Conference < ApplicationRecord
   # Reports an error when such a condition is found
   def valid_times_range?
     if start_hour && end_hour
-      errors.add(:start_hour, 'is lower than 0') if start_hour < 0
+      errors.add(:start_hour, 'is lower than 0') if start_hour.negative?
       errors.add(:end_hour, 'is lower or equal than start hour') if end_hour <= start_hour
       errors.add(:end_hour, 'is greater than 24') if end_hour > 24
     end
@@ -843,7 +842,7 @@ class Conference < ApplicationRecord
   def weeks(start_week, end_week)
     weeks = end_week - start_week + 1
     weeks_of_year = Date.new(start_date.year, 12, 31).strftime('%W').to_i
-    weeks < 0 ? weeks + weeks_of_year : weeks
+    weeks.negative? ? weeks + weeks_of_year : weeks
   end
 
   ##
@@ -961,7 +960,7 @@ class Conference < ApplicationRecord
   # * +True+ -> One difficulty level or more
   # * +False+ -> No diffculty level
   def difficulty_levels_set?
-    program.difficulty_levels.count > 0
+    program.difficulty_levels.count.positive?
   end
 
   ##
@@ -971,7 +970,7 @@ class Conference < ApplicationRecord
   # * +True+ -> One difficulty level or more
   # * +False+ -> No diffculty level
   def event_types_set?
-    program.event_types.count > 0
+    program.event_types.count.positive?
   end
 
   ##
@@ -981,7 +980,7 @@ class Conference < ApplicationRecord
   # * +True+ -> One track or more
   # * +False+ -> No track
   def tracks_set?
-    program.tracks.count > 0
+    program.tracks.count.positive?
   end
 
   ##
@@ -991,7 +990,7 @@ class Conference < ApplicationRecord
   # * +True+ -> One room or more
   # * +False+ -> No room
   def rooms_set?
-    venue.present? && venue.rooms.count > 0
+    venue.present? && venue.rooms.count.positive?
   end
 
   # Checks if the conference has a venue object.
@@ -1097,19 +1096,19 @@ class Conference < ApplicationRecord
   # * +hash+ -> hash
   def self.calculate_user_distribution_hash(active_user, unconfirmed_user, dead_user)
     result = {}
-    if active_user > 0
+    if active_user.positive?
       result['Active'] = {
         'color' => 'green',
         'value' => active_user
       }
     end
-    if unconfirmed_user > 0
+    if unconfirmed_user.positive?
       result['Unconfirmed'] = {
         'color' => 'red',
         'value' => unconfirmed_user
       }
     end
-    if dead_user > 0
+    if dead_user.positive?
       result['Dead'] = {
         'color' => 'black',
         'value' => dead_user
diff --git a/app/models/event.rb b/app/models/event.rb
index 943572eb..c0361868 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -120,7 +120,15 @@ class Event < ApplicationRecord
       @total_rating += vote.rating
     end
     @total = votes.size
-    @total_rating > 0 ? number_with_precision(@total_rating / @total.to_f, precision: 2, strip_insignificant_zeros: true) : 0
+    if @total_rating.positive?
+      number_with_precision(
+        @total_rating / @total.to_f,
+        precision:                 2,
+        strip_insignificant_zeros: true
+      )
+    else
+      0
+    end
   end
 
   # get event speakers with the event sumbmitter at the first position
@@ -310,7 +318,7 @@ class Event < ApplicationRecord
 
   def before_end_of_conference
     errors
-        .add(:created_at, "can't be after the conference end date!") if program.conference && program.conference.end_date &&
+        .add(:created_at, "can't be after the conference end date!") if program.conference&.end_date &&
         (Date.today > program.conference.end_date)
   end
 
@@ -322,7 +330,7 @@ class Event < ApplicationRecord
   # Allow only confirmed tracks that belong to the same program as the event
   #
   def valid_track
-    return unless track && track.program && program
+    return unless track&.program && program
     errors.add(:track, 'is invalid') unless track.confirmed? && track.program == program
   end
 
diff --git a/app/models/program.rb b/app/models/program.rb
index 14554786..a6c7aff3 100644
--- a/app/models/program.rb
+++ b/app/models/program.rb
@@ -80,7 +80,7 @@ class Program < ApplicationRecord
     tracks.self_organized.confirmed.order(start_date: :asc).each do |track|
       event_schedules += track.selected_schedule.event_schedules.order(start_time: :asc) if track.selected_schedule
     end
-    event_schedules.sort_by(&:start_time) if event_schedules
+    event_schedules&.sort_by(&:start_time)
   end
 
   ##
@@ -134,7 +134,7 @@ class Program < ApplicationRecord
   # * +false+ -> If rating is not enabled
   # * +true+ -> If rating is enabled
   def rating_enabled?
-    rating && rating > 0
+    rating&.positive?
   end
 
   ##
@@ -240,7 +240,9 @@ class Program < ApplicationRecord
   # Check if schedule_interval is a divisor of 60 minutes
   #
   def schedule_interval_divisor_60
-    errors.add(:schedule_interval, 'must be a divisor of 60') if schedule_interval > 0 && 60 % schedule_interval > 0
+    if schedule_interval.positive? && 60 % schedule_interval.positive?
+      errors.add(:schedule_interval, 'must be a divisor of 60')
+    end
   end
 
   ##
@@ -248,7 +250,7 @@ class Program < ApplicationRecord
   #
   def unschedule_unfit_events
     unfit_schedules = event_schedules.select do |event_schedule|
-      event_schedule.start_time.min % schedule_interval > 0
+      event_schedule.start_time.min % schedule_interval.positive?
     end
     EventSchedule.where(id: unfit_schedules.map(&:id)).destroy_all
   end
diff --git a/app/models/registration.rb b/app/models/registration.rb
index 45d2d55b..536392dc 100644
--- a/app/models/registration.rb
+++ b/app/models/registration.rb
@@ -77,7 +77,8 @@ class Registration < ApplicationRecord
   end
 
   def registration_limit_not_exceed
-    if conference.registration_limit > 0 && conference.registrations(:reload).count >= conference.registration_limit
+    if conference.registration_limit.positive? &&
+       conference.registrations(:reload).count >= conference.registration_limit
       errors.add(:base, 'Registration limit exceeded')
     end
   end
diff --git a/app/models/registration_period.rb b/app/models/registration_period.rb
index 9aa82444..dadb1ae1 100644
--- a/app/models/registration_period.rb
+++ b/app/models/registration_period.rb
@@ -11,10 +11,10 @@ class RegistrationPeriod < ApplicationRecord
 
   def before_end_of_conference
     errors
-    .add(:start_date, "can't be after the conference end date (#{conference.end_date})") if conference && conference.end_date && start_date && (start_date > conference.end_date)
+    .add(:start_date, "can't be after the conference end date (#{conference.end_date})") if conference&.end_date && start_date && (start_date > conference.end_date)
 
     errors
-    .add(:end_date, "can't be after the conference end date (#{conference.end_date})") if conference && conference.end_date && end_date && (end_date > conference.end_date)
+    .add(:end_date, "can't be after the conference end date (#{conference.end_date})") if conference&.end_date && end_date && (end_date > conference.end_date)
   end
 
   def start_date_before_end_date
diff --git a/app/models/ticket_purchase.rb b/app/models/ticket_purchase.rb
index 15de3785..2c63fc85 100644
--- a/app/models/ticket_purchase.rb
+++ b/app/models/ticket_purchase.rb
@@ -48,7 +48,7 @@ class TicketPurchase < ApplicationRecord
   end
 
   def self.purchase_ticket(conference, quantity, ticket, user)
-    if quantity > 0
+    if quantity.positive?
       purchase = new(ticket_id: ticket.id,
                      conference_id: conference.id,
                      user_id: user.id,
@@ -65,7 +65,7 @@ class TicketPurchase < ApplicationRecord
                                     user_id: user.id,
                                     paid: false).first
 
-    purchase.quantity = quantity if quantity > 0
+    purchase.quantity = quantity if quantity.positive?
     purchase
   end
 
diff --git a/app/models/track.rb b/app/models/track.rb
index 01755c0e..b53d7944 100644
--- a/app/models/track.rb
+++ b/app/models/track.rb
@@ -113,10 +113,8 @@ class Track < ApplicationRecord
   def revoke_role_and_cleanup
     role = Role.find_by(name: 'track_organizer', resource: self)
 
-    if role
-      role.users.each do |user|
-        user.remove_role 'track_organizer', self
-      end
+    role&.users&.each do |user|
+      user.remove_role 'track_organizer', self
     end
 
     self.selected_schedule_id = nil
diff --git a/app/models/user.rb b/app/models/user.rb
index d062529a..a7a279c5 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -126,7 +126,7 @@ class User < ApplicationRecord
   def self.for_ichain_username(username, attributes)
     user = find_by(username: username)
 
-    raise UserDisabled if user && user.is_disabled
+    raise UserDisabled if user&.is_disabled
 
     if user
       user.update_attributes(email: attributes[:email],
diff --git a/app/models/venue.rb b/app/models/venue.rb
index 6a758242..9ef8b109 100644
--- a/app/models/venue.rb
+++ b/app/models/venue.rb
@@ -19,7 +19,7 @@ class Venue < ApplicationRecord
 
   def country_name
     name = ISO3166::Country[country]
-    name.name if name
+    name&.name
   end
 
   def location?
diff --git a/app/views/admin/events/_datatable_row.haml b/app/views/admin/events/_datatable_row.haml
index 17cf7560..4f361338 100644
--- a/app/views/admin/events/_datatable_row.haml
+++ b/app/views/admin/events/_datatable_row.haml
@@ -1,5 +1,6 @@
-- cache ['admin/events/index', conference_id, event, event.submitter, event.speakers, event_types, tracks, difficulty_levels] do
-  %tr{id: "event-#{event.id}"}
+- cache ['admin/events/index', conference_id, event, event.submitter,
+  event.speakers, event_types, tracks, difficulty_levels] do
+  %tr{ id: "event-#{event.id}" }
     %td
       = event.id
 
@@ -38,7 +39,8 @@
       = event_switch_checkbox(event, :require_registration, conference_id)
       - if event.require_registration
         = link_to registered_text(event),
-          registrations_admin_conference_program_event_path(conference_id, event),
+          registrations_admin_conference_program_event_path(conference_id,
+            event),
           class: 'btn btn-xs btn-default'
 
     %td.text-center{ data: { order: event.is_highlight.to_s } }
diff --git a/app/views/admin/events/_datatable_row_rating.haml b/app/views/admin/events/_datatable_row_rating.haml
index 99ff49ec..8e3e9c29 100644
--- a/app/views/admin/events/_datatable_row_rating.haml
+++ b/app/views/admin/events/_datatable_row_rating.haml
@@ -2,11 +2,11 @@
   %div{ data: { toggle: 'tooltip' }, title: rating_tooltip(event, max_rating) }<
     = rating_stars(event.average_rating, max_rating, avgrate: true)
 
-%div.clearfix
+.clearfix
   - if event.voted?(current_user)
     %span.label.label-success
       You voted:
-      = "#{event.user_rating(current_user)}/#{max_rating}"
+      = rating_fraction(event.user_rating(current_user), max_rating)
   - else
     %span.label.label-danger
       Not rated
diff --git a/app/views/admin/events/_export_menu.haml b/app/views/admin/events/_export_menu.haml
index 233986df..e7743d23 100644
--- a/app/views/admin/events/_export_menu.haml
+++ b/app/views/admin/events/_export_menu.haml
@@ -1,4 +1,4 @@
-%div.btn-group
+.btn-group
   %button.btn.btn-success.dropdown-toggle{ data: { toggle: 'dropdown' } }
     Export
     = export_format.upcase
diff --git a/db/migrate/20141128073306_migrate_data_remove_column_include_cfp_in_splash_add_column_include_cfp.rb b/db/migrate/20141128073306_migrate_data_remove_column_include_cfp_in_splash_add_column_include_cfp.rb
index 2f794f75..169bcfb3 100644
--- a/db/migrate/20141128073306_migrate_data_remove_column_include_cfp_in_splash_add_column_include_cfp.rb
+++ b/db/migrate/20141128073306_migrate_data_remove_column_include_cfp_in_splash_add_column_include_cfp.rb
@@ -17,7 +17,7 @@ class MigrateDataRemoveColumnIncludeCfpInSplashAddColumnIncludeCfp < ActiveRecor
     TempConference.all.each do |conference|
       cfp = TempCallForPaper.find_by(conference_id: conference.id)
 
-      if cfp && cfp.include_cfp_in_splash
+      if cfp&.include_cfp_in_splash
         splashpage = TempSplashpage.find_or_initialize_by(conference_id: conference.id)
         splashpage.include_cfp = cfp.include_cfp_in_splash # true
         splashpage.save!
diff --git a/lib/tasks/events_registrations.rake b/lib/tasks/events_registrations.rake
index 726b739b..ea0254dd 100644
--- a/lib/tasks/events_registrations.rake
+++ b/lib/tasks/events_registrations.rake
@@ -5,7 +5,7 @@ namespace :events_registrations do
       duplicates = EventsRegistration.all.map { |er| er.id if er.valid? == false}.compact
 
       puts "Duplicates found: #{duplicates.count}"
-      if duplicates.count > 0
+      if duplicates.count.positive?
         puts "With IDs: #{duplicates}"
       end
 
diff --git a/spec/helpers/events_helper_spec.rb b/spec/helpers/events_helper_spec.rb
index 93c75272..61768afc 100644
--- a/spec/helpers/events_helper_spec.rb
+++ b/spec/helpers/events_helper_spec.rb
@@ -19,16 +19,16 @@ describe EventsHelper, type: :helper do
     end
   end
 
-  describe "#rating_tooltip" do
+  describe '#rating_tooltip' do
     let(:max_rating) { 5 }
     let(:event) { create(:event) }
     let(:average_rating) { "#{event.average_rating}/#{max_rating}" }
     let(:vote_count) { pluralize(event.voters.length, 'vote') }
 
-    it "includes the average rating" do
+    it 'includes the average rating' do
       expect(rating_tooltip(event, max_rating)).to match(average_rating)
     end
-    it "includes the vote count" do
+    it 'includes the vote count' do
       expect(rating_tooltip(event, max_rating)).to match(vote_count)
     end
   end