electronics, metals, chemical and pharmaceutical, food and beverages, and other manufacturing. Young firms are more likely to achieve high growth. Among firms that survive for more than three years, about 3 in every 10 new firms achieves HGF status and they generate more than 70% of the jobs generated by new firms.

Our paper contributes to a wider literature analyzing the dynamics of HGF by bringing additional evidence from developing countries. We present several stylized facts on HGF patterns in Tunisia that are complementary to previous knowledge available for OECD countries.<sup>7</sup> This finding is consistent with previous research focusing in Tunisia (Rijkers et. al. 2014, Arouri et. al. 2016, and Arouri et. al. 2018) showing that small firms generate most of the jobs, but this relationship is driven by firm entry and the fact that most entrants start small. These findings are also in line with Haltiwanger et al. (2013) for the United States.

The remainder of the paper is organized as follows. Section 2 reviews the literature and presents the key HGF definitions used in this paper. Section 3 describes the data and analyzes the share of HGFs across time and across sectors. Section 4 describes the HGF dynamics in terms of entry and survival rates, growth, and jobs generation across different firm age cohorts. Section 5 analyzes the firm characteristics associated with high-growth status across HGF definitions, and section 6 concludes.

# **2. HGF definition**

Since the seminal contributions of Birch and Medoff (1994) and Birch et al. (1995), the literature has defined HGF in many different ways. Most of these studies tend to agree on using turnover or number of employees to measure growth (see for instance Autio et al. 2000, Bottazzi and Secchi 2006, Goedhuys and Sleuwaegen 2010, Copass 2013, Holzl 2014, Daunfeldt and Halvarssonin 2016, and Bianchini and Secci 2016, Haltiwanger et. al., 2017). The growth measures using turnover or number of employees are the most available in enterprise surveys worldwide, which make it possible to compare HGFs across countries. We can classify these approaches in two groups: i) Absolute percentage growth (with fixed growth rate or fixed share of top performing firms); ii) Combined growth and initial size measures.

A well-known HGF definition in the first group is provided by OECD (2007). It defines HGF as all enterprises with average annualized growth greater than 20% per annum, over a three-year period, measured by number of employees or turnover. Moreover, this definition uses a 10employee minimum threshold to eliminate firms with a small number of jobs, for which a small change (e.g. 1 job) can lead to high growth rates. This threshold is contested in some circumstances, because it can significantly influence the number of HGFs in the data set.<sup>8</sup> An

> 7 The OECD report Entrepreneurship at a Glance (OECD 2017) has been publishing several indicators of HGF annually, but mostly concentrated on OECD countries.

> 8 For example, Clayton et al. (2013) and Daunfeldt et al. (2015) find that at least 75% of firms in the US private sector and 95% of surviving firms in Sweden, respectively, are smaller than 10 employees.

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