A set of preliminary search results is retrieved based on a search query, the set of search results including a plurality of pay-per-click listings. A normalized click-through rate is calculated for each pay-per-click listing in the set of preliminary search results, the normalized click-through rate being based on an actual click-through rate that is adjusted according to one or more positions in which the pay-per-click listing was previously provided in one or more sets of final search results. The plurality of pay-per-click listings is ordered based on the calculated normalized click-through rates.