def extract_populations_and_criteria
      has_observation = extract_observations
      document_populations = get_document_populations
      number_of_populations = document_populations.length
      document_populations.each_with_index do |population_def, population_index|
        population = {}
        handle_base_populations(population_def, population)

        id_def = get_id_def(population_def)
        add_id_to_population(id_def, population, population_index)
        add_title_to_population(population_def, population)
        add_observ_to_population(has_observation, population)

        add_supplemental_data_elements_to_population(population_def, population)

        @populations << population
        handle_stratifications(population_def, number_of_populations, population, id_def, population_index)
      end

      # Push in the stratification populations after the unstratified populations
      @populations.concat(@stratifications)
      [@populations, @population_criteria]
    end
def extract_populations_and_criteria
      has_observation = extract_observations
      document_populations = get_document_populations
      number_of_populations = document_populations.length
      document_populations.each_with_index do |population_def, population_index|
        population = {}
        handle_base_populations(population_def, population)

        id_def = get_id_def(population_def)
        add_id_to_population(id_def, population, population_index)
        add_title_to_population(population_def, population)
        add_observ_to_population(has_observation, population)

        add_supplemental_data_elements_to_population(population_def, population)

        @populations << population
        handle_stratifications(population_def, number_of_populations, population, id_def, population_index)
      end

      # Push in the stratification populations after the unstratified populations
      @populations.concat(@stratifications)
      [@populations, @population_criteria]
    end
Returns the population descriptions and criteria found in this document