Assignment Branch Condition

method.rb

# Get Catalogue Sections
# Returns 3 arrays of resource objects (frontmatter, catalogue, backmatter)
def catalogue_sections
  contents    = sort_catalogue_contents
  frontmatter = contents.find_all { |p| p.data.sort_order <= 10 }
  backmatter  = contents.find_all { |p| p.data.sort_order > 100 }
  catalogue   = contents.find_all do |p|
    p.data.sort_order > 10 && p.data.sort_order <= 100
  end

  frontmatter.sort_by! { |p| p.data.sort_order }
  catalogue.sort_by! { |p| p.data.sort_order }
  backmatter.sort_by! { |p| p.data.sort_order }

  return frontmatter, catalogue, backmatter
end

It means that your method is too big, that it's doing too much. In this case one could argue that it contains too much duplication.

A bit computer sciency, but here's the definition: http://c2.com/cgi/wiki?AbcMetric