I can adjust the shape of nodes using commands such as minimum width or inner xsep, but these require explicit units. When I scale the entire figure (\begin{tikzpicture} [scale=0.5]) it does not scale the node.
NOTE The following question does not solve my problem: Using scalable sizes for rectangles, circles and nodes in TikZ?
Because when I add arrows from the node they do not recognize the shapes that I drew around the node.
\documentclass[twoside]{article}
\usepackage{tikz}
\usetikzlibrary{calc,shapes,arrows}
\begin{document}
\begin{tikzpicture} [scale=1]
\draw (0,0) circle (1.5) node (A) {A};
\draw (0,4) circle (1.5) node (B) {B};
\draw [->] (A) -- (B);
\end{tikzpicture}
\end {document}
transform shapein the picture options for all nodes or in the node options for individual selection. So that question doesn't but the linked one in that question solves your problem; http://tex.stackexchange.com/questions/29662/what-are-the-guidelines-for-making-tikz-pictures-properly-scalable – percusse Sep 25 '13 at 21:07