DATA COLLECTION AND VALIDATION REN21 has developed a unique renewable energy reporting culture, allowing it to become recognised as a neutral data and knowledge broker that provides credible and widely accepted information. Transparency is at the heart of the REN21 data and reporting culture, and the following text explains some of the GSR's key processes for data collection and validation. DATA COLLECTION Production of REN21's GSR is a continuous process occurring on an annual basis. The data collection process begins following the launch of the previous year's report with an Expression of Interest form to mobilise REN21's GSR contributors. During this time, the GSR team also prepares the questionnaires that will be filled in by contributors. The questionnaires are updated each year with emerging and relevant topics as identified by the REN21 Secretariat. The data collection process involves the following elements: Open data collection. In the open data collection questionnaire, contributors from around the world submit data on renewable energy in their respective countries or countries of interest. This covers information on annual developments in renewable energy technologies, market trends, policies and local perspectives. The questionnaire also collects data related to energy access from respondents – with a focus on developing and emerging countries – on the status of electrification and clean cooking as well as policies and programmes for energy access and markets for distributed renewables. Each data point is provided with a source and verified independently by the REN21 GSR team. Data collection with the country questionnaire typically begins in October. Regional contributors. For some world regions, REN21 appoints one principal data contributor to provide specific renewable energy data across different sectors and to share an overview of general trends and developments of renewables in the specific region. Peer review. To further collect data and project examples and to ensure that significant developments have not been overlooked, GSR contributors and reviewers participate in an open peer review process that takes place twice during each report cycle. For GSR 2023, the peer review round for theRenewables in Energy Demand module occurred in November 2022 for outlines and in January 2023 for the full draft. The peer review rounds for the Renewables in Energy Supply, the Renewable Energy Systems and Infrastructure, and the Renewables for Economic and Social Value Creation modules took place in December 2022 for outlines and was scheduled to occur in April 2023 for the full draft as well as for the Global Overview. Peer review is open to all interested experts. Expert interviews. REN21's global community consists of a wide range of professionals who provide their expert input on renewable energy trends in the target year through interviews and personal communication with the REN21 GSR team and chapter authors. The vast majority of the information is backed up by primary sources. Desk research. To fill in remaining gaps in the GSR and to pursue new topics, the REN21 GSR team and chapter authors conduct extensive desk research. Topics of research vary widely between GSR years and depend on emerging topics, important trends and annual availability of formal or informal data in the target sector. Policy database (national, sub-national, cities). The REN21 GSR team compiles data on policy-specific indicators, especially targets and policies. This is collected from regional contributors and through desk research. For the city-level data, this builds also on existing consolidated datasets at the global or regional level. Data-sharing agreements. REN21 holds several data-sharing agreements with some of the largest and most reliable data providers/aggregators in the energy sector. These formal data are used exclusively in some cases or, in others, form the foundation of calculations and estimations presented in the GSR. DATA VALIDATION REN21 ensures the accuracy and reliability of its reports by conducting data validation and fact checking as a continuous process. Beginning during the first submission of the country questionnaires, data are continually verified up through the design period and until the final report is published. All data provided by contributors, whether written or verbal, are validated by primary sources, which are published alongside the full report.