How to create a complex table?

A great place to start, when you don't know how to do a table (or something else in LaTeX) is wikibooks.

In the following I'll use the packages booktabs and multirow for they allow me to insert specific rules and cell entries spanning more then one row/column. As your example uses a sans-serif font, I used \renewcommand*\familydefault{\sfdefault} to reproduce this.

The tabular* environment allows to set a specific width, in this case \linewidth; a sidenote, for larger tables you could switch to landscape-mode.

For more information concerning tables, check out the wikibooks link.

Now here how you could realize the table you want in LaTeX.

Code

\documentclass{article}

\usepackage{booktabs}
\usepackage{multirow}
\renewcommand*\familydefault{\sfdefault}

\begin{document}

\begin{tabular*}{\linewidth}{ @{\extracolsep{\fill}} ll *{13}c @{}}
\toprule
Measures & Task & \multicolumn{4}{c}{Method1} &
\multicolumn{4}{c}{Method2} & \multicolumn{4}{c}{Method3} & p-value \\
\midrule \midrule \addlinespace \\
 & & 1 & 2 & 3 & 4 & 1 & 2 & 3 & 4 & 1 & 2 & 3 & 4 & \\
\cmidrule{3-6} \cmidrule{7-10} \cmidrule{11-14} \cmidrule{15-15}
\addlinespace \\
\multirow{3}{*}{Quality} & A  \\
                         & B  \\
                         & C  \\
                         \midrule \addlinespace \\
\multirow{3}{*}{Time}    & A  \\
                         & B  \\
                         & C  \\
                         \midrule \addlinespace \\
\multirow{3}{*}{Costs}   & A  \\
                         & B  \\
                         & C  \\
\bottomrule
\end{tabular*}

\end{document}

Output

Here is the table:

Here is the code to typeset the table:

\begin{tabular}{@{}lllllllllllllllll@{}}
  \toprule
  Measures & Task &\multicolumn{4}{c}{Method1} & & \multicolumn{4}{c}{Method2} & &\multicolumn{4}{c}{Method3} & p-value \\
  \midrule
  && 1 & 2 & 3 & 4 & & 1 & 2 & 3 & 4 & & 1 & 2 & 3 & 4 & \\
  \cmidrule{3-6} \cmidrule{8-11} \cmidrule{13-16}
  \multirow{3}{*}{Quality} & A \\
  & B \\
  & C \\
  \midrule
  \multirow{3}{*}{Time} & A \\
  & B \\
  & C \\
  \midrule
  \multirow{3}{*}{Cost} & A \\
  & B \\
  & C \\
  \bottomrule
\end{tabular}
\end{document}

Some explanations:

• Use booktabs package to get better row spacing and rules. Note the different use of \toprule, \bottomrule and \midrule.

• Let an empty column between the columns that have a partial rule \cmidrule.

• In the column specification use @{} at the beginning and end. In this way the rules are not longer than the table itself.
• Use the package multirow to center in multiple rows.
• Don't use double rules.