I am trying to format a booktabs table with multirow content. I am aware that vertical rules go against the booktabs style. However, in this table, it seems to me that some kind of vertical guide would help parsing across multiple rows. So I came up with huge curly brackets. My code and a figure of the current table is below. Is there a better (and nicer) way to aid parsing in this table - an alternative to what I have done below?
\documentclass{article}
\usepackage{amsthm,amsmath,amssymb,booktabs,array, multirow, rotating}
% For the huge curly brackets
\makeatletter
\newcommand{\Vast}{\bBigg@{2.5}}
\makeatother
\makeatletter
\newcommand{\Vastt}{\bBigg@{4.3}}
\makeatother
\makeatletter
\newcommand{\Vasttt}{\bBigg@{5.4}}
\makeatother
\makeatletter
\newcommand{\Vastttt}{\bBigg@{9.6}}
\makeatother
\begin{document}
\begin{sidewaystable}[!htb]
\caption{\textbf{Title of the table}}\label{tab2}
\begin{tabular}{@{}llllll@{}}
\midrule
\multicolumn{1}{l}{\textbf{Charac1}}
& \multicolumn{2}{c}{\textbf{Characteristics II}}
& \multicolumn{1}{c}{\textbf{Thing1}}
& \multicolumn{1}{c}{\textbf{Thing2}}
& \multicolumn{1}{c}{\textbf{Thing3}}\\\cmidrule(lr){2-3}
& \multicolumn{1}{c}{\textbf{Subthing1}}
& \multicolumn{1}{c}{\textbf{Subthing2}} & & &\\
\midrule
\multicolumn{1}{l}{XXX}
&\multicolumn{1}{c}{$\pi_{XXX}$}
&\multicolumn{1}{l}{None}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{}
&\multicolumn{1}{>{}c}{} \\\cmidrule(lr){1-2}
\multicolumn{1}{l}{XX}
&\multicolumn{1}{c}{$\eta_{XX}$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{\multirow{-2}{*}[0.5em]{{\Vast\}}Something here}}
&\multicolumn{1}{c}{}
&\multicolumn{1}{>{}c}{} \\\cmidrule(lr){1-2}
\multicolumn{1}{l}{XX}
&\multicolumn{1}{c}{$\zeta_{XXX}$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{}
&\multicolumn{1}{>{}l}{}\\\cmidrule(lr){1-2}
\multicolumn{1}{l}{XX}
&\multicolumn{1}{c}{$\epsilon$}
&\multicolumn{1}{l}{\multirow{-3}{*}[1.4em]{{\Vastt\}}Something}}
&\multicolumn{1}{l}{\multirow{-2}{*}[0.7em]{{\Vast\}}Something else}}
&\multicolumn{1}{c}{}
&\multicolumn{1}{>{}l}{} \\\cmidrule(lr){1-2}
\multicolumn{1}{l}{XX}
&\multicolumn{1}{c}{$\omega_{XX}$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{Something else}
&\multicolumn{1}{c}{}
&\multicolumn{1}{c}{} \\\cmidrule(lr){1-2}
\multicolumn{1}{l}{XX}
&\multicolumn{1}{c}{$\epsilon_{XXX}$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{c}{}
&\multicolumn{1}{c}{}
&\multicolumn{1}{>{}l}{}\\\cmidrule(lr){1-2}
\multicolumn{1}{l}{XX}
&\multicolumn{1}{c}{$\alpha$}
&\multicolumn{1}{l}{\multirow{-3}{*}[1.1em] {{\Vastt\}}Something}}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{\multirow{-7}{*}[3em]{{\Vastttt\}} Thing1+Thing3)}}
&\multicolumn{1}{>{}c}{\multirow{-7}{*}[1.5em]{\textit{Something else}}} \\\cmidrule(lr){1-2}
\multicolumn{1}{l}{XXX}
&\multicolumn{1}{c}{$XYZ=1$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{}
&\multicolumn{1}{>{}l}{}\\\cmidrule(lr){1-2}
\multicolumn{1}{l}{XXXX}
&\multicolumn{1}{c}{$XYZ_{AB}$}
&\multicolumn{1}{l}{\multirow{-2}{*}[0.5em]{{\Vast\}}Attribute}}
&\multicolumn{1}{l}{\multirow{-4}{*}[1.6em]{{\Vasttt\}}Something else}}
&\multicolumn{1}{l}{\multirow{-2}{*}[0.5em]{{\Vast\}}Things (thing1 \& thing2)}}
&\multicolumn{1}{l}{\multirow{-2}{*}[0.5em]{\textit{Something more}}}\\
\midrule
\end{tabular}
\\
\footnotesize{\textbf Some footnote}
\end{sidewaystable}\clearpage
\end{document}
Currently the output looks thus:
I am running up against a blank wall on ideas. Thanks for any guidance on this.
--------EDIT with a somewhat cleaner-looking solution----------------
Thanks to guidance from @ChrisS, @Werner and @cfr in the comments below, I coded a small redesign to the table, and it definitely looks much cleaner - even without the vertical rules. Code and final table below for reference (this was for an article here):
\documentclass[11pt]{article}
\usepackage[margin=0.75in]{geometry}
\usepackage[utf8]{inputenc}
\usepackage{amsthm,amsmath,amssymb,booktabs,array, multirow,rotating}
\makeatletter
\newcommand{\Vast}{\bBigg@{2.5}}
\makeatother
\makeatletter
\newcommand{\Vastt}{\bBigg@{4.3}}
\makeatother
\makeatletter
\newcommand{\Vasttt}{\bBigg@{5.4}}
\makeatother
\makeatletter
\newcommand{\Vastttt}{\bBigg@{9.6}}
\makeatother
\thispagestyle{empty}
\begin{document}
\begin{sidewaystable}[!htb]
\renewcommand\thetable{2}
\caption{\textbf{Summary of the modeling approaches included in the evaluation}}\label{tab2}
\begin{tabular}{@{}llllll@{}}
\midrule
\multicolumn{1}{l}{\textbf{Model}}
& \multicolumn{2}{c}{\textbf{Ensemble Characteristics}}
& \multicolumn{1}{c}{\textbf{Output}}
& \multicolumn{1}{c}{\textbf{Paradigm}}
& \multicolumn{1}{c}{\textbf{R Package}}\\\cmidrule(lr){2-3}
& \multicolumn{1}{c}{\textbf{Tuning parameter}}
& \multicolumn{1}{c}{\textbf{Model Space Construction}} & & &\\
\midrule
\multicolumn{1}{l}{ENC}
&\multicolumn{1}{c}{$\lambda_{ENC}$}
&\multicolumn{1}{l}{None}
&\multicolumn{1}{l}{Influential variables}
&\multicolumn{1}{l}{}
&\multicolumn{1}{>{}c}{} \\\cmidrule(lr){1-4}
\multicolumn{1}{l}{PS}
&\multicolumn{1}{c}{$\lambda_{MB}$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{Influential variables}
&\multicolumn{1}{c}{}
&\multicolumn{1}{>{}c}{} \\\cmidrule(lr){1-2}\cmidrule(lr){4-4}
\multicolumn{1}{l}{LS}
&\multicolumn{1}{c}{$\lambda_{ENC}$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{Inclusion probabilities}
&\multicolumn{1}{l}{}
&\multicolumn{1}{>{}l}{}\\\cmidrule(lr){1-2}\cmidrule(lr){4-4}
\multicolumn{1}{l}{SS}
&\multicolumn{1}{c}{$\Lambda$}
&\multicolumn{1}{l}{\multirow{-3}{*}[1.2em]{{\Vastt\}}Subsampling}}
&\multicolumn{1}{l}{Inclusion probabilities}
&\multicolumn{1}{c}{}
&\multicolumn{1}{>{}l}{} \\\cmidrule(lr){1-4}
\multicolumn{1}{l}{PR}
&\multicolumn{1}{c}{$\lambda_{MB}$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{Influential variables}
&\multicolumn{1}{c}{}
&\multicolumn{1}{c}{} \\\cmidrule(lr){1-2}\cmidrule(lr){4-4}
\multicolumn{1}{l}{LR}
&\multicolumn{1}{c}{$\lambda_{ENC}$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{Inclusion probabilities}
&\multicolumn{1}{c}{}
&\multicolumn{1}{>{}l}{}\\\cmidrule(lr){1-2}\cmidrule(lr){4-4}
\multicolumn{1}{l}{SR}
&\multicolumn{1}{c}{$\Lambda$}
&\multicolumn{1}{l}{\multirow{-3}{*}[1.2em] {{\Vastt\}}Resampling}}
&\multicolumn{1}{l}{Inclusion probabilities}
&\multicolumn{1}{l}{\multirow{-7}{*}[3em]{{\Vastttt\}} Frequentist ($l_{1}, l_{2}$ penalties)}}
&\multicolumn{1}{>{}c}{\multirow{-7}{*}[1.7em]{\textit{quadrupen, glmnet}}} \\\cmidrule(lr){1-6}
\multicolumn{1}{l}{BMA}
&\multicolumn{1}{c}{$EMS=1$}
&\multicolumn{1}{c}{}
&\multicolumn{1}{l}{Inclusion probabilities}
&\multicolumn{1}{l}{}
&\multicolumn{1}{>{}l}{}\\\cmidrule(lr){1-2}\cmidrule(lr){4-4}
\multicolumn{1}{l}{BMAC}
&\multicolumn{1}{c}{$EMS_{CV}$}
&\multicolumn{1}{l}{\multirow{-2}{*}[0.5em]{{\Vast\}}MCMC}}
&\multicolumn{1}{l}{Inclusion probabilities}
&\multicolumn{1}{l}{\multirow{-2}{*}[0.5em]{{\Vast\}}Bayesian (Spike \& slab prior)}}
&\multicolumn{1}{l}{\multirow{-2}{*}[0.2em]{\textit{BoomSpikeSlab}}}\\
\midrule
\end{tabular}
\footnotesize{\textbf{ENC:} The baseline penalized regression model. Elastic net with $\lambda_{optimal} =\lambda_{ENC}$ derived from cross-validation (CV), \textbf{Ensembles based on 100 subsamples:} \textbf{PS:} Meinshausen \& B{\"u}hlmann's algorithm with a single $\lambda_{optimal} = \lambda_{MB}$ selected to minimize the expected number of false positives, \textbf{LS:} Single $\lambda_{optimal} = \lambda_{ENC}$ with no variable selection, \textbf{SS:} Stability selection across the entire 100 $\lambda \in \Lambda$ grid with no variable selection, \textbf{Ensembles based on 100 resamples: }\textbf{PR, LR, SR:} Identical to PS, PR and LR, respectively, with model space constructed through resampling. \textbf{BMA:} Bayesian model averaging with expected model size ($EMS$) = 1, \textbf{BMAC:} BMA with EMS determined by CV ($EMS_{CV}$).}
\end{sidewaystable}\clearpage
\end{document}
This is how it looks now:
Things (thing1 & thing2)
brace the same scope asAttribute
?Thing3
seems superfluous...