economic growth. These results show negative effects in 2001-2015, whereas the positive effects found in Choi and Yi (2009) correspond to 1991-2000. Maurseth (2018) suggests that the greatest benefits of ICT adoption could lie a decade or more in the past. Similarly, Edquist et al. (2018) find that a 10 percent increase in mobile broadband (MBB) network adoption (measured as the percentage of total connections) causes, on average, a 0.8 percent increase in GDP but with a decreasing impact over time (disappearing 6 years after introduction), and it is smaller in magnitude in OECD countries.

More recently, studies have tried to address the question of whether there are additional economic impacts with the adoption of newer mobile technologies. Bahia et. al (2019) investigate the impact of the rollout of mobile broadband technologies on GDP growth from 2000 to 2017 across more than 160 countries. The period under analysis covers the deployment of 2G technology until the roll-out of 4G. The authors find that, in general, a 10 percent increase in the adoption of (any) mobile technology is associated with an increase in GDP between 0.5 and 1.2 percent. This impact is 15 percent higher when connections are upgraded from 2G to 3G, and 25 percent higher when transitioning from 2G to 4G. The study also notes that the impacts are larger in countries with high education levels, suggesting a relationship between human capital and the potential gains of ICT adoption. Concerns about endogeneity are addressed using structural equations models, dynamic panel data, and instrumental variables. Haftu et al. (2019) also find that the expansion of mobile phone subscribers in 40 Sub-Saharan African countries had a significant positive causal effect on increases in the region’s per capita GDP reported between 2006 and 2015. Explicitly, a 10 percent increase in mobile phone penetration in the region increases by 1.2 percent the GDP per capita. Contrary to these results, the authors find that internet penetration has not contributed to GDP per capita growth during 2006-2015. The authors claim that this could be due to the low internet penetration in the region, high technology illiteracy, or limited technological infrastructure, among others.

The literature on causal effects is sparser but, to a large extent, it points at positive causal effects of ICT adoption on growth. Castaldo et al. (2018), use General Method of Moments— Instrumental Variable (GMM-IV) to find a positive and statistically significant causal effect between fixed broadband and economic growth in 23 OECD countries between 1996 and 2010, even after controlling for countries’ initial endowments (measured as fixed capital formation). Similarly, based on panel co-integration and Granger causality tests, Arvin and Pradhan (2014) claim a causal relationship between broadband adoption and GDP growth using data for 19 countries—developed and developing—between 1998 and 2011. Furthermore, the study finds a bidirectional relationship between GDP growth and broadband penetration only in developed countries. In contrast, in developing countries, the authors find that economic growth has a causal effect on broadband penetration. Gruber et al. (2014) use simultaneous equations models to conclude that fixed broadband adoption has had a significant positive causal effect on GDP growth in 27 countries in the European Union from 2005 to 2011. The authors argue that the effect is larger in high adoption countries. More recently, Calderon and Cantu (2020) examine the impact of digital infrastructure on the development of Sub-Saharan Africa, by comparing data from 177 countries between 1990 and 2019. The authors use a principal component analysis (PCA) and general method of moments with instrumental variables (GMM-IV) system estimator to find a positive and significant causal impact of digital infrastructure 7