\documentclass[tikz,border=6pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,positioning}

\begin{document}
\begin{tikzpicture}[
  >=Latex,
  node distance = 2.4cm,
  var/.style = {
    draw = black!70,
    line width = 0.5pt,
    rounded corners = 3pt,
    minimum width = 2.25cm,
    minimum height = 0.9cm,
    align = center,
    font = \small
  },
  arrow/.style = {
    ->,
    line width = 0.65pt,
    draw = black!65
  }
]

\node[var, fill = orange!16] (oil)     at (0, -1.55) {\texttt{oil}\\{\scriptsize oil producer}};
\node[var, fill = blue!10]   (reg)     at (3,  1.15) {\texttt{reg}\\{\scriptsize democracy}};
\node[var, fill = yellow!18] (edt)     at (3, -1.15) {\texttt{edt}\\{\scriptsize education}};
\node[var, fill = green!10]  (growth)  at (6.4,  0.00) {$\log(\texttt{gdpw})$\\{\scriptsize growth level}};

\draw[arrow] (oil.east) -- (reg.west);
\draw[arrow] (oil.south east) .. controls (2.0,-2.75) and (5.2,-2.20) .. (growth.south west);
\draw[arrow] (reg.south) -- (edt.north);
\draw[arrow] (edt.east) -- (growth.south west);
\draw[arrow] (reg.east) -- (growth.north west);

\end{tikzpicture}
\end{document}
