Ofgem has adopted a price control regulatory framework with a balanced objective of enhancing and developing electricity networks for the future, controlling costs to customers and allowing DNOs, such as WPD's DNOs, to earn a fair return on their investments. This regulatory structure is focused on outputs and performance in contrast to traditional U.S. utility ratemaking that operates under a cost recovery model. Price controls are established based on long-term business plans developed by each DNO with substantial input from its stakeholders. To measure the outputs and performance, each DNO business plan includes incentive targets that allow for increases and/or reductions in revenues based on operational performance, which are intended to align returns with quality of service, innovation and customer satisfaction.
The "Statement of Income Analysis" discussion below describes significant changes in principal line items on PPL's Statements of Income, comparing 2019 with 2018. The "Segment Earnings" and "Adjusted Gross Margins" discussions for PPL provide a review of results by reportable segment. These discussions include non-GAAP financial measures, including "Earnings from Ongoing Operations" and "Adjusted Gross Margins," and provide explanations of the non-GAAP financial measures and a reconciliation of those measures to the most comparable GAAP measure. The "2020 Outlook" discussion identifies key factors expected to impact 2020 earnings.
Tables analyzing changes in amounts between periods within "Statement of Income Analysis," "Segment Earnings" and "Adjusted Gross Margins" are presented on a constant GBP to U.S. dollar exchange rate basis, where applicable, in order to isolate the impact of the change in the exchange rate on the item being explained. Results computed on a constant GBP to U.S. dollar exchange rate basis are calculated by translating current year results at the prior year weighted-average GBP to U.S. dollar exchange rate.
A "Statement of Income Analysis" is presented separately for PPL Electric, LKE, LG&E and KU. The "Statement of Income Analysis" discussion below describes significant changes in principal line items on the Statements of Income, comparing 2019 with 2018. The results of operations section for PPL Electric, LKE, LG&E and KU is presented in a reduced disclosure format in accordance with General Instructions (I)(2)(a) of Form 10-K.