With labels like "gazelles," "cheetahs" and "unicorns," high-growth firms are a rare phenomenon in entrepreneurship that have a big impact on the economy. According to a new Entrepreneurship Policy Digest released today by the Ewing Marion Kauffman Foundation, given their outsized contributions to the economy, it is important to understand high-growth firms and how their impacts are measured.The Digest highlights findings from the Kauffman Index of Growth Entrepreneurship, including the top 40 metro area high-growth business rankings, and these national trends:    Growth entrepreneurship is increasing, though not at historic highs    High-growth average employment growth rose    High-tech is not a pre-requisite for high-growth; other sectors are growing too    The number of high-growth firms varies within industries from year to yearHigh-growth firms expand to numerous locations and encourage employment growth, accounting for as much as 50 percent of new jobs created. The Policy Digest explains how defining high-growth businesses using firm attributes – venture capital funding and participation in accelerators – will capture different results than defining them by business performance metrics – revenue growth, employment and exits.The Digest recommends these strategies to encourage an environment for growth entrepreneurship:    Increase college completion rates    Welcome and retain immigrant entrepreneurs    Limit non-compete agreements