Do you really have to use itemize environment for this purpose? Why not using, e.g., align environment:
Code: Select all
\documentclass{article}
\usepackage{amsmath}
\newcommand{\lbr}[1][6]{\displaybreak[1]\\[#1pt]}% a command to simplify optional line break in the midst of an equation, with a default value of 6pt
\begin{document}
\begin{align*}
\text{recall} &= TP/(TP+FN)\lbr
\text{precision} &= TP/(TP+FP)\lbr
\text{TP rate} &= \text{recall}\lbr[12]% manually inserted vertical spacing, 12pt
\text{FP rate} &= FP/(FP+TN)
\end{align*}
\end{document}
P.S. To allow an equation to be broken across pages, use
\displaybreak or
\allowdisplaybreak commands (take a look at
amsmath manual, section 3.9).