  This paper considers an often forgotten relationship, the time delay between
a cause and its effect in economies and finance. We treat the case of Foreign
Direct Investment (FDI) and economic growth, - measured through a country Gross
Domestic Product (GDP). The pertinent data refers to 43 countries, over
1970-2015, - for a total of 4278 observations. When countries are grouped
  according to the Inequality-Adjusted Human Development Index (IHDI), it is
found that a time lag dependence effect exists in FDI-GDP correlations.
  This is established through a time-dependent Pearson 's product-moment
correlation coefficient matrix.
  Moreover, such a Pearson correlation coefficient is observed to evolve from
positive
  to negative values depending on the IHDI, from low to high. It is
"politically and policy
  "relevant" that
  the correlation is statistically significant providing the time lag is less
than 3 years. A "rank-size" law is demonstrated.
  It is recommended to reconsider such a time lag effect when discussing
previous analyses whence conclusions on international business, and thereafter
on forecasting.
