The effect of optimal population growth on technology growth, Optimal cross- country analysis

Today, population growth is one of the most important issues facing the countries because it affects the patterns of sustainable economic growth. Population growth is a key element of semi-endogenous economic growth models. Semi-endogenous growth states that economic growth is correlated with the growth rate of effort in research and development. The common features of these models are decreasing returns of knowledge in the production of new knowledge and positive population growth.
The aim of this study is to investigate the long-run relationships between population growth on technological output (patents), focusing on eight developing Islamic countries group named D8, in order to analyze the range of population growth rates favorable to support higher technological output. In particular, the aim is to determine whether the relationship between population growth and technological output is an inverted-U shape. In this research, focusing on two critical variables -population growth and technological outputs- the non-linear model to investigate the relation between this two variables is used. This is important that it determines the optimal level in which population growth rates tend to be associated to higher technological outputs. The results show the existence of an inverted-U shaped curve between population growth rate and technological output. Sustainable population growth rate of about 2% is consistent with the increase in technological outputs. Also, population growth rates much different from optimal growth rate of population can reduce the returns of technological outputs to population growth.