Few small and medium-sized enterprises (SMEs) scale up but these few firms are the major driver of new jobs added to OECD economies. In the aftermath of the global COVID-19 crisis, scalers can play a key role in getting growth back on track. In contrast to the 2007-08 global crisis, the potential of scalers seems to be strong as countries rolled out unprecedented policy responses to support viable firms facing extraordinary -but temporary -challenges. However, firms, and particularly SMEs that aim to scale up, still face barriers in unleashing their growth potential such as finding workers with the right skills, making the most of new digital tools or integrating into global value chains.A better understanding of the characteristics of scalers and of the transformation process that they undertake is essential for effective policy design to address growth barriers. This report highlights the wide and varied range of firms with scaling-up potential, pointing towards the need for equally varied policy support. Often, policy packages target only a small share of potential scalers, such as recent start-ups, firms in high-technology sectors or prospective (ever-elusive) unicorns, i.e. privately held companies with a capital-based valuation of USD 1 billion or more. But there are opportunities to unlock growth and job creation in many other types of firms. With the right policy mix in place, scalers can play a key role in transforming new opportunities into jobs and economic growth. However, without detailed knowledge of the characteristics of scalers, policy makers might target their efforts at only a fraction of firms with scaling-up potential or support them with the wrong tools.This report provides new evidence on scalers based on analysis of detailed firm-level data from a pilot project implemented in Finland, Italy, Portugal, the Slovak Republic and Spain. The project serves as proof of concept of the value of opening up the wealth of data locked in the vaults of OECD member countries. Different authorities in the five pilot countries agreed to work with the OECD to facilitate access to their confidential microdata sources. In-depth analysis is possible as national statistical offices and other authorities in the participating countries have made significant efforts to link a wide range of data sources that allow for a much better understanding of the firms that are or will become scalers. A harmonised approach in defining scalers, analysing their performance and exploring their characteristics allows for direct comparison of the results between the five countries.Being a pilot project, the report illustrates the powerful potential of leveraging on microdata, and, in turn, what is possible in many (if not all) OECD member countries by better capitalising on existing data within countries. In that sense, through the provision of powerful new policy messages and indicators -without increasing response burdens and without breaching confidentiality -the project is also intended to provide motivation and momentum for o...