Can I make this table fit in portrait mode?

Question

I have a table which I want to make fit in portrait mode. Do you think this is possible?

Here is the minimal example:

\documentclass[11pt,a4paper]{book}
\usepackage[utf8x]{inputenc}
\usepackage{ucs}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{makeidx}
\usepackage{graphicx}
\usepackage[width=0.00cm, height=0.00cm, left=1.00in, right=1.00in, top=1.00in, bottom=1.00in]{geometry}
\usepackage{threeparttable}
\usepackage{rotating}
\usepackage{booktabs}

\begin{document}

{\footnotesize
\begin{table}[H!]
%\begin{sidewaystable}[h!]
\centering
\begin{threeparttable}
\caption{OLS results } \label{ols_results}
\begin{tabular}{lcccccccc} \toprule
& \multicolumn{4}{c}{Non-HMO Hospitals} & \multicolumn{4}{c}{HMO-Hospitals} \\
\cmidrule(r){2-5} \cmidrule{6-9}
& \multicolumn{2}{c}{Doctors} & \multicolumn{2}{c}{Non-Doctors} & \multicolumn{2}{c}{Doctors} & \multicolumn{2}{c}{Non-Doctors} \\
\cmidrule(r){2-3} \cmidrule(r){4-5} \cmidrule(r){6-7} \cmidrule{8-9}

 & Mean &  StDev & Mean &  StDev & Mean &  StDev & Mean &  StDev \\ \midrule
\underline{Demographics}: &&&&&&&& \\
Age & 32.59* &  [4.00] & 31.13* &   [4.28] & 32.63* &   [4.12] & 30.69* &   [4.28] \\
Mother's Education ($\%$) &&&&&&&& \\ 
\hspace{0.2em} Some college &&&&&&&& \\
\hspace{0.2em} College graduate &&&&&&&& \\
\hspace{0.2em} High education &&&&&&&& \\
Father's education &&&&&&&& \\
\hspace{0.2em} Some college &&&&&&&& \\
\hspace{0.2em} College graduate &&&&&&&& \\
\hspace{0.2em} High education &&&&&&&& \\
Insurance ($\%$) &&&&&&&& \\
\hspace{0.2em} HMO &&&&&&&& \\
\hspace{0.2em} Government &&&&&&&& \\
\hspace{0.2em} Indigent &&&&&&&& \\
Placental/uterine rupture/haemorrhage & 1.44 & [0.23] &&&&&& \\ \midrule
Observations & \multicolumn{2}{c}{2360} & \multicolumn{2}{c}{7852} & \multicolumn{2}{c}{256} & \multicolumn{2}{c}{879}  \\
\bottomrule
\end{tabular}

\begin{tablenotes}
\tiny
\item[a] [whatever here, this is just a test] This table is made with the use if \LaTeXe{} . Cristobal is a port on the Atlantic side of the Panama Canal. It is located on the western edge of Manzanillo Island and is part of the Panamanian city and province of Colon. Cristobal Colon is the Spanish translation for Christopher Columbus, the Genovese explorer for whom these places were named.
\end{tablenotes}

\end{threeparttable}
%\end{sidewaystable}
\end{table}
}


\end{document}

Answer 1

The footnotesize is being ignored in your example because it is outside of the table environment. If you move it inside then the fnot is small enough to show the table in the page.

To center it on the page I used the environment used in this answer to fit boxes that are too large for the margins. However, that will not work if your table is a float (but judging from your [H!] maybe that's not too serious?). Other greater minds may come up with a better solution, but this might do.

\documentclass[11pt,a4paper]{book}
\usepackage[
  width=0.00cm,
  height=0.00cm,
  left=1.00in,
  right=1.00in,
  top=1.00in,
  bottom=1.00in,
  showframe
]{geometry}
\usepackage{threeparttable}
\usepackage{booktabs}

\newenvironment{xcenter}
{\par\setbox0=\hbox\bgroup\ignorespaces}
{\unskip\egroup\noindent\makebox[\textwidth]{\box0}\par}

\begin{document}

\begin{xcenter}
\footnotesize
% \centering
\begin{threeparttable}
\caption{OLS results } \label{ols_results}
\begin{tabular}{@{}lcccccccc@{}} \toprule
& \multicolumn{4}{c}{Non-HMO Hospitals} & \multicolumn{4}{c}{HMO-Hospitals} \\
\cmidrule(r){2-5} \cmidrule{6-9}
& \multicolumn{2}{c}{Doctors} & \multicolumn{2}{c}{Non-Doctors} & \multicolumn{2}{c}{Doctors} & \multicolumn{2}{c}{Non-Doctors} \\
\cmidrule(r){2-3} \cmidrule(r){4-5} \cmidrule(r){6-7} \cmidrule{8-9}

& Mean &  StDev & Mean &  StDev & Mean &  StDev & Mean &  StDev \\ 
\midrule
\underline{Demographics}: &&&&&&&& \\
Age & 32.59* &  [4.00] & 31.13* &   [4.28] & 32.63* &   [4.12] & 30.69* &   [4.28] \\
Mother's Education ($\%$) &&&&&&&& \\ 
\hspace{0.2em} Some college &&&&&&&& \\
\hspace{0.2em} College graduate &&&&&&&& \\
\hspace{0.2em} High education &&&&&&&& \\
Father's education &&&&&&&& \\
\hspace{0.2em} Some college &&&&&&&& \\
\hspace{0.2em} College graduate &&&&&&&& \\
\hspace{0.2em} High education &&&&&&&& \\
Insurance ($\%$) &&&&&&&& \\
\hspace{0.2em} HMO &&&&&&&& \\
\hspace{0.2em} Government &&&&&&&& \\
\hspace{0.2em} Indigent &&&&&&&& \\
Placental/uterine rupture/haemorrhage & 1.44 & [0.23] &&&&&& \\ 
\midrule
Observations & \multicolumn{2}{c}{2360} & \multicolumn{2}{c}{7852} & \multicolumn{2}{c}{256} & \multicolumn{2}{c}{879}  \\
\bottomrule
\end{tabular}

\begin{tablenotes}
\tiny
\item[a] [whatever here, this is just a test] This table is made with the use if \LaTeXe{} . Cristobal is a port on the Atlantic side of the Panama Canal. It is located on the western edge of Manzanillo Island and is part of the Panamanian city and province of Colon. Cristobal Colon is the Spanish translation for Christopher Columbus, the Genovese explorer for whom these places were named.
\end{tablenotes}

\end{threeparttable}
\end{xcenter}

\end{document}

Answer 2

If you're willing to allow a line break in the header of the second-to-last row (Placental/uterine rupture/haemorrhage), you can get the table to fit into the text block in portrait mode by changing the type of the first, i.e., left-most, column from l to p{4cm}. Why 4 centimeters? So that the next-longest header, Mother's Education (\%), fits in the available space. Note that it's no longer necessary to reduce the font size.

I would also suggest a more systematic trimming of the \cmidrules in order to make the structure of the header rows more self-evident. And, in keeping with the general design philosophy that pervades the booktabs package, I'd get rid of the whitespace to the left of the first column and the right of the final column. One way to do so is to use a tabular* environment, to set \tabcolsep to 0pt, and to let LaTeX figure out how much intercolumn whitespace is optimal.

The thin lines to the left and right of the image below denote the edges of the text block; the lines are inserted by the showframe option of the geometry package.

\documentclass[11pt,a4paper]{book}
\usepackage[margin=1in,showframe]{geometry}
\usepackage{threeparttable,booktabs}
\begin{document}

\begin{table}
\centering
\begin{threeparttable}
\setlength\tabcolsep{0pt}
\caption{OLS results} \label{ols_results}
\begin{tabular*}{\textwidth}{ p{4cm} @{\extracolsep{\fill}} cccccccc } 
\toprule
& \multicolumn{4}{c}{Non-HMO Hospitals} 
& \multicolumn{4}{c}{HMO-Hospitals} \\
\cmidrule(lr){2-5} \cmidrule(l){6-9}
& \multicolumn{2}{c}{Doctors} & \multicolumn{2}{c}{Non-Doctors} 
& \multicolumn{2}{c}{Doctors} & \multicolumn{2}{c}{Non-Doctors} \\
\cmidrule(lr){2-3} \cmidrule(lr){4-5} \cmidrule(lr){6-7} \cmidrule(l){8-9}
 & Mean &  StDev & Mean &  StDev 
 & Mean &  StDev & Mean &  StDev \\ 
\midrule
\underline{Demographics}: &&&&&&&& \\
Age & 32.59* &  [4.00] & 31.13* &   [4.28] & 32.63* &   [4.12] & 30.69* &   [4.28] \\
Mother's Education (\%) &&&&&&&& \\
\hspace{0.2em} Some college &&&&&&&& \\
\hspace{0.2em} College graduate &&&&&&&& \\
\hspace{0.2em} High education &&&&&&&& \\
Father's education &&&&&&&& \\
\hspace{0.2em} Some college &&&&&&&& \\
\hspace{0.2em} College graduate &&&&&&&& \\
\hspace{0.2em} High education &&&&&&&& \\
Insurance (\%) &&&&&&&& \\
\hspace{0.2em} HMO &&&&&&&& \\
\hspace{0.2em} Government &&&&&&&& \\
\hspace{0.2em} Indigent &&&&&&&& \\
\raggedright Placental\slash uterine rupture\slash 
   haemorrhage & 1.44 & [0.23] &&&&&& \\ 
\midrule
Observations 
& \multicolumn{2}{c}{2360} & \multicolumn{2}{c}{7852} 
& \multicolumn{2}{c}{256} & \multicolumn{2}{c}{879}  \\
\bottomrule
\end{tabular*}  
\begin{tablenotes}
\footnotesize
\item[a] [whatever here, this is just a test] This table is made with the use of \LaTeXe. Cristobal is a port on the Atlantic side of the Panama Canal. It is located on the western edge of Manzanillo Island and is part of the Panamanian city and province of Colon. Cristobal Colon is the Spanish translation for Christopher Columbus, the Genoese explorer for whom these places were named.
\end{tablenotes}
\end{threeparttable}
\end{table}
\end{document}