Centering table horizontally within page using threeparttable

Question

I’m sure this has been addressed somewhere before, but I’m having difficulty finding the answer and would greatly appreciate some help. I’ve tried inserting \centering or using the center environment in various places and can’t seem to figure it out.

I’m trying to center the table within the page, but it seems like the use of threeparttable pushes the table to the left - causing it to start immediately after the left margin. I want the distance from the table to the left edge of the page to be equal to the distance from the table to the right edge of the page. Here’s an example of my current setup:

\documentclass[authoryear, review, 12pt, times]{elsarticle}
\usepackage[top=1in, bottom=1in, left=1in, right=1in]{geometry}
\usepackage{setspace}  % has commands for singlespacing, onehalfspacing, and doublespacing
\usepackage{mathrsfs}
\usepackage{IEEEtrantools}
%\usepackage{multirow}
\usepackage{booktabs}
\usepackage{threeparttable}
\usepackage{array}
\usepackage{caption}
\usepackage{graphicx}
\usepackage{tabu}

\newcolumntype{L}[1]{>{\raggedright\arraybackslash}p{#1}}  % These 3 lines define new column types mainly to allow for centered column of user defined width
\newcolumntype{C}[1]{>{\centering\arraybackslash}p{#1}}
\newcolumntype{R}[1]{>{\raggedleft\arraybackslash}p{#1}}
%\pagenumbering{gobble}      % Supresses page number 

\begin{document}

\begin{table}[ht!]
\begin{threeparttable}
\bfseries{\footnotesize{Table 1. Test Table.}} \\ [2mm]
\scriptsize
\normalfont
\begin{tabular}[pos]{L{7.0cm} R{2.0cm}} 
\toprule
\multicolumn{2}{c}{Dependent Variable: Outcome Var} \\ 
\midrule
$Variable 1$ & 0.123 \\
& (1.00) \\ [1.5mm]
$Variable 2$ & 0.456 \\
& (1.65) \\ [1.5mm]
$Variable 3$ & 0.789 \\
& (1.96) \\ [1.5mm]
$Variable 4$ & 1.123 \\
& (2.59) \\ [1.5mm]
$Variable 5$ & 1.456 \\
& (3.00) \\ [1.5mm]
$Variable 6$ & 1.789 \\
& (3.20) \\ [1.5mm]
$Variable 7$ & 2.000 \\
& (3.50) \\ [10.0mm]

Some Info & Yes \\ [0.5mm]
Other Info & No \\ [0.5mm]
Observations & Ample \\ [0.5mm]
Random Statistic & 1,505.37 \\ [0.5mm]
Last Piece of Info & 100.00 \\
\bottomrule
\end{tabular}
\centering
\caption{
\normalfont{\textnormal{This table displays information. It is just being used to see if I can actually center this thing, which has proved more difficult than anticipated. }}}
\label{tab:Test}
\end{threeparttable}
\end{table}
\end{document}

Answer 1

There are two issues with your code:

• There's no \centering instruction between \begin{table} and \begin{threeparttable}.

• A threeparttable environment has three [surprise!] formal components: a caption, a tabular (or tabular*, or tabularx, etc) environment, and a tablenotes environment. With this in mind, the instruction

  \bfseries{\footnotesize{Table 1. Test Table.}} \\ [2mm]
  

  is out of place. You should either remove it or incorporate it in the tabular environment.

With these two adjustments, your formatting objective will be achieved immediately.