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author | Norbert Preining <norbert@preining.info> | 2019-09-02 13:46:59 +0900 |
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committer | Norbert Preining <norbert@preining.info> | 2019-09-02 13:46:59 +0900 |
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tree | 60335e10d2f4354b0674ec22d7b53f0f8abee672 /usergrps/uktug/baskervi/4_5/reese.tex |
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diff --git a/usergrps/uktug/baskervi/4_5/reese.tex b/usergrps/uktug/baskervi/4_5/reese.tex new file mode 100644 index 0000000000..3ee9c022e1 --- /dev/null +++ b/usergrps/uktug/baskervi/4_5/reese.tex @@ -0,0 +1,474 @@ +\title{\LaTeX{} and tables} +\author[R. Allan Reese]{R. Allan Reese\\ Computer Centre\\Hull + University\\ +\texttt{r.a.reese@ucc.hull.ac.uk}} + +\begin{Article} + +\section{Tables} + +Kroonenberg's article on tables (\cite{Kroo}) made some useful +suggestions on \LaTeX{} coding but the examples left much to be +desired as patterns to follow. I fully agree that the \LaTeX{} User +Guide (\cite{lamport}), \cite{kopka} and virtually every book +on word processing place far too much stress on rules as boxes. +\cite{chapman} gives better guidance on the presentation of +tables; I particularly enjoy commending this book, as it challenges one +of the Great Lies of Life.\footnote{I'm from the Government and I'm here +to help you.} Ehrenberg's short article (\cite{ehrena}) should be studied +by anyone putting figures into a table. \cite{reynolds} is a +more general book and discusses presentations of all types. + +Chapman gives clear, straightforward guidance with many examples of +good and bad practice. Here, for example, is a point almost +always overlooked by people who believe `a picture is worth a thousand +words': +\begin{quote} +``Since neither charts nor tables ever `speak for +themselves', in order to communicate a message effectively either must +be accompanied by a verbal summary.'' +\end{quote} + +Tabular material tends to be complex. For a recent workshop on table +construction in \LaTeX{}, I selected what seemed to me the simplest +tables from journals to hand. The criteria for simplicity were small +size and not appearing to need a wide variety of \LaTeX{} commands. In +serious use, you would expect to use more commands than when teaching, +so this restriction would be relaxed. More complex tables were often +`tables within tables', for which \LaTeX's analytical approach of +defining logical units is well suited. However, another of Chapman's +truths that is easily swept aside by an author's enthusiasm is: +\begin{quote} ``Tables should be +small. It is better to include three or four compact tables, each +illustrating one or two points succinctly, rather than construct a +single large table which is then referred to in text covering a large +number of paragraphs or pages.'' +\end{quote} + +Her next sentence will strike a chord with any \LaTeX{} user: +\begin{quote} +``Small tables are easier to position close to their verbal summary, and +are easier to include in the main report.'' +\end{quote} + +Several problems arose in recreating the examples using \LaTeX. Some +were due to the desire to reproduce the table exactly as seen, rather +than re-present the information in a natural way. On the other hand, +the exercise did bring out the flexibility of \LaTeX's standard +tabulation tools. + +The short workshop was successful, in that most of my (Computer Centre) +colleagues were able to add further lines into a part-built table +despite having no previous experience of \LaTeX. They followed the +layout by copying the commands that they saw; this contrasts greatly +with WYSIWYG word processors where you may see a table but have no +idea of how it was constructed. + +\LaTeX{} is an excellent program for formatting tables. It is not, +however, realistic to expect tables to be laid out optimally first +time and automatically. This is one area where the author must be +prepared to make judgements and manual adjustments. + +\section{Rules of thumb} + +Rules for constructing tables can be divided into those dealing with the +content and those dealing with the layout. The typesetter will generally +have little say in the content or ordering of the information, but an +editor might (should) make suggestions. The evidence of most journals +suggests their editors are not as critical of tables or graphics as of +text. + +Chapman distinguishes between demonstration tables and reference +tables. The reader uses the former to perceive a pattern and the +latter to look up a value. Tables that try to do both are rarely +successful. Ehrenberg's examples would come under the demonstration +category, for which he suggests: +\begin{enumerate} +\item give marginal averages to provide a visual focus +\item order the rows or columns by the marginal averages or some +relevant measure of size +\item put figures to be compared in columns rather than in +rows (i.e., to aid mental arithmetic) +\item round all numbers to two effective digits, unless the exact +value is for reference +\end{enumerate} +See \cite{ehrena} and 1978 for further explanation and discussion. + +Layout can make a table easier to read\Dash or can destroy its +meaning. + +Sweep away the black boxes and apply two principles. A table is a +discontinuity in reading. The reader is not to scan it linearly, as if +reading text. You must therefore guide their eyes: +\begin{enumerate} +\item use white space to separate objects +\item use lines (rules) to join or point connections. +\end{enumerate} + +As when setting text, beginners tend to add too much space, though +Chapman complains that even professional compositors like to widen +tables to fill the text width. Physically compact tables are easier +to scan. \cite{visdis} makes this point about graphics; make them +smaller so the reader can see the pattern not the dots. This applies +also to tables. White space is used to set off the table from the body +text, usually by centering. Spaces within the table are used to indent +hierarchical headings and to break the table into sections. In another +article (\cite{reesettn}) I discuss \LaTeX{} constructs for interposing +space after a set number of lines or when the initial letter changes. + +Horizontal rules are standard at top and bottom to further demarcate +the table. There is usually a thick rule under the table heading, a +thin rule under the banner (column) headings and a thin rule between +the table body and any explanatory notes. Incidentally, one of +Chapman's warning examples shows how disastrous it is to rely on the reader +reading the footnotes to understand the table. They must be strictly +to expand or qualify a detail. + +Kroonenberg mentions the problem of text coming too close to rules. +This can be adjusted with struts or non-aligned \verb|\vspace|; I like to +insert a small extra space above the first row and after the last, to +unify the body of the table and distinguish it from the headings. +Vertical rules are used sparingly, if at all. It is better to put +a little space between stubs (row labels) and the `data' columns, and +between the columns and the marginal `averages', than to add rules +crossing the direction of scanning. You can help the reader scan +across gaps by adding leaders, or by centering rather than justifying +short items. + +Use a smaller font inside tables. Kroonenberg implies this by +discussing sans serif fonts ``to set off the table.'' It is another +way to make the table more compact and visually distinguished. + +Telephone directories are large reference tables which demonstrate +these principles. They are set in the smallest readable font size, +have leaders to bridge the gap between name and number, and are +usually multi-column with white space separators. + +\section{Implementation} + +The layout principles are easily implemented in standard \LaTeX. The +table itself uses the \verb|tabular| environment. The number of +columns will often be greater than at first apparent, with many +multicolumn items. For example, this is a natural way to handle +hierarchical stubs, where the primary labels span two columns and the +secondary labels start in column two (indented). \LaTeX{} will +calculate column widths but it is often desirable to force several +columns to have the same width. Headings will often require either +\verb|\multicolumn| or \verb|\noalign| to position them aesthetically. + +\LaTeX{} 2.09 had only \verb|\hline| and \verb|\cline|. The +\verb|hhline| package is worth fetching from CTAN\@. Line spacing for +the whole table can be adjusted with \verb|\arraystretch| and made +different from \verb|\baselinestretch|. Bear in mind that the table +can be compressed as well as extended, and \verb|\arraystretch|$=0.9$ +may make the pattern more obvious and the table \emph{more} readable. + +The table is then embedded in an environment to set it off from the +text. You can choose from \verb|quote|, \verb|center|, display maths or +\verb|table|. Set the font size smaller within that environment, sans +serif for the table and body text style for the captions. (The examples +in this article follow their originals as closely as possible and don't +do this. I think they would be improved if they did.) The table +environment makes the object into a float, hence not to be broken +between pages and with a cross-referencing label. The \verb|longtable| +package caters for tables that are too large for a single page. + +Some mechanism should be used to create a left and right indent, the +most obvious being to define the table width explicitly and center it. +\verb|minipage| puts the footnotes to the table at the bottom of the table, +using different marks from those in the body text. Putting the +\verb|minipage| round the \verb|table| rather than just the +\verb|tabular| also makes the caption narrower. I prefer the table +reference to stand out, and often use the \verb|hangcapt| package. + +When there are several tables or a house style, it is better to +define a new environment to ensure consistency in their presentation. +I also commonly define new length constants for use in tables rather +than copy the values. + +\section{A \LaTeX{} gap} + +One common format for tables has rows of short data values but a final +column containing texts. The description parameter may therefore tell +\LaTeX{} to calculate the widths of data columns from the values, but +the final column will be a \verb|parbox| and should sensibly use the +remainder of the \verb|linewidth|. This is one need that \LaTeX{} (2.09) +blatantly fails to meet. You have to set the width of a \verb|parbox| or +\texttt{p}(aragraph) column. Kroonenberg implies this problem when discussing +\verb|\raggedright|; as she points out, to choose unjustified text you +have to enclose each text in a \verb|parbox|. This is less work if the width +is set as a name (to be calculated) and not the numeric length. My +pragmatic solution is to set the value for the final column initially +to the \verb|\linewidth|, run \LaTeX{}, note (from the log) the +overfill, and subtract that from \verb|\linewidth|. + +\section{Kroonenberg's `after' table} + +The `after' table of Economic Forecasts is still poor. This is partly +due to the content. It lacks a text explanation (possibly the primary +source had one), but I \emph{guess} that the intention is to compare +forecasts from two sources. Numbers going \emph{down} the columns are +not related (in this sense), so flipping (transposing) the table would +make logical sense. This might be the best solution on a wider page, +as having the table span two columns is yet another way of +distinguishing it from the body. If we insist on keeping it within one +(text) column, there is room for another column of values as a +`margin'. + +Without a rubric, I cannot decide if the table is trying to show +disagreement between the two sets of forecasts, or similarity. +Dependent on the message, the best margin might be the difference +between each pair of forecasts, a $+$/$-$ sign for higher or lower, +the ratio, or the average. The forecasts themselves should all be +rounded to two significant digits. + +We seem to have lost between the `before' and `after' the detail that +the figures are percentages; and \emph{was} government income really a +`percentage change of a percentage'? The labels that include ($\times$ +1000 persons) are misleading; I take that notation to mean that the +numbers shown \emph{have been} multiplied by 1000 (like \TeX{} +magnifications). The correct notation would be (000s of persons). + +Making the rules extend to the linewidth was presumably not thought +out. They unbalance the design, and all the white space implies an +omission. The spaces between the columns are too wide. If ``mutations +w.r.t.~1991'' and ``absolute quantities'' are to be used as primary +divisions, then the secondary stubs (``real consumption'' etc) should +be indented. If you think too deeply about the title, are these +forecast changes or changes to (earlier) forecasts? Follow Chapman's +advice and split the table into two, with headings of the form +``Forecast percentage changes 1991/92 in National Economy'' and +``Forecast quantities\ldots''. I leave +this redrafting as an exercise for the reader. + +A parenthetic remark for those preparing tables of accounts comes from +\cite{townsend}. He suggests that ``statements comparing budgets +to actual should be written not in the usual terms of higher (lower) +but in plain English of better (or worse) than predicted by the +budget. This eliminates the mental gear changes between income items +(where parentheses are bad) and expense items (where parentheses are good).'' +Typography helping the reader. + + +\section{New examples} + +The following examples are shown as output, in the expectation that +the interested reader will obtain the `input' from the +the author or the editor. If there is sufficient interest, the \LaTeX\ +source for the tables can be placed on the CTAN archives. + +\subsection{Example 1\Dash Cohabitation} + +This is taken from \textit{Key Data 88} (\cite{key}) which had itself +extracted it from \textit{Social Trends}. \textit{Key Data} is a sample of +UK government statistics published annually as an educational resource +and a guide to the more extensive sources. The table as printed had +inconsistencies in the use of italic and upright fonts, and in its +indentation. +\begin{table*} +\begin{center} +\caption{Cohabitation} +\label{cohab} +% The table in the book is sans-serif with the heading bold. +{\sffamily +\setlength{\doublerulesep}{0pt} +\begin{tabular}{llrrrrr} +\multicolumn{7}{p{.5\textwidth}}% +{\begin{tabbing} +\bf 2.12\quad \= Percentage of women aged 18--49 cohabiting:\\ + \> by age +\end{tabbing}}\\ +\multicolumn{2}{c}\textit{Great Britain}& + \multicolumn{5}{r}{Percentage and numbers}\\ +\hline +\hline + & & 1979 & 1981 & 1983 & 1984 & 1985 \\ +\hline +\multicolumn{2}{l}{Age group \textit{(percentages)}} \\ +\hspace*{1em} & \textit{18--24} & 4.5 & 5.6 & 5.2 & 7.3 & 9.1 \\ + & \textit{25--49} & 2.2 & 2.6 & 3.2 & 3.3 & 3.9 \\ +\multicolumn{2}{c}\textit{All aged 18--49} + & 2.7 & 3.3 & 3.6 & 4.2 & 5.0 \\ +\\ +\multicolumn{2}{l}{Women in sample \textit{(numbers)}} \\ + & (=100\% above)\\ + & 18--24 & 1,353 & 1,517 & 1,191 & 1,174 & 1,182 \\ + & 25--49 & 4,651 & 5,007 & 4,094 & 4,070 & 4,182 \\ + \cline{3-7} +\multicolumn{2}{c}\textit{All aged 18--49} + & 6,004 & 6,524 & 5,285 & 5,244 & 5,364\\ +\hline +\hline +\end{tabular} +} +\end{center} +\end{table*} + +Table~\ref{cohab} could be further improved by a distinct split and +putting the two halves the other way round: ``Numbers of women surveyed +in each year, in two age groups'' and ``Of the samples, percentage +cohabiting''. Note that the first half is essentially for reference and +the second half for demonstration. + +\subsection{Example 2\Dash Vulture meat} + +Table~\ref{meat} is taken from Ibis (\cite{thibault}), journal of the British +Ornithologists' Union. It is a simple table, but appears in a two-column +layout and has footnotes. The original used numbers as the footnote +markers. I found this disconcerting, as \textit{G${}^\mathrm{2}$} looks +like a numeric power; so I'll use the \LaTeX{} default in a minipage, +which also sets the table to the width of an Ibis column. + +This table is adequate for reference, and is discussed in an adjacent +text. ``Comparison of food availability among territories showed +significant differences.\ \ldots'' The rows are not in an obvious order, +and if the primary aim is to compare the number of, say, sheep in each +territory, it might have been better flipped. A marginal total of the +number of prey animals, or their biomass, in each territory would have +been helpful. It is debatable whether the figures should be rounded, +since they are taken from previous studies which are themselves recorded +or reported with different precisions. +\begin{table}[H] +\begin{center} +\begin{minipage}{81mm} +\caption{\em Numbers of ungulates in Lammergeier territories +(except for wild boar, differences among territories are statistically +significant, $\chi^2_{16}=16.825, \mbox{P} < 0.001$).}\label{meat} +\vspace{1ex}\ \\ +\renewcommand{\footnoterule}{\rule{0pt}{0pt}} +\begin{tabular*}{81mm}{l@{\quad\extracolsep{\fill}}rrrrr} +\hline\vspace{.4ex}\\ +& \multicolumn{5}{c}{Territory}\vspace{.2ex}\\ +\cline{2-6}\vspace{.2ex}\\ +Species & \textit{B}\footnote{Dubray \& Roux(1990)} +& \textit{G}\footnote{Anonymous (1989).} +& \textit{R}\footnote{Direction \dots} +& \textit{T}${}^\alph{mpfootnote}$ % Gash way of repeating superscript. +& \textit{V}${}^\alph{mpfootnote}$ +\\ +\hline\vspace{.2ex}\\ +Sheep & 2000 & 1400 & 5240 & 3165 & 3480 \\ +Mouflon & $<200$ & $-$ & $-$ & $<400$ & $<5$ \\ +Goat & 570 & 4142 & 1880 & 1510 & 820 \\ +Cattle & 2300 & 6402 & 7204 & 6774 & 965 \\ +Pig & 3400 & 7188 & 1900 & 400 & 522 \\ +Boar & $+$\footnote{$+ =$ present. $- =$ absent.} + & $+$ & $+$ & $+$ & $+$\\[.5ex] +\vspace{.2ex}\\ +\hline +\end{tabular*} +\end{minipage} +\end{center} +\end{table} + + +\subsection{Example 3\Dash YOPs} + +The problem with this table from \cite[p11 and, slightly changed, +p35]{chapman} is that one column has an entry spreading over several +lines (the brace linking them). The hint for doing this is in +\cite[p79]{kopka}, but they show only one optional argument to +\verb|\raisebox|. Using both optional arguments (setting height and +depth to zero) and putting the `brace array' on the line opposite its +middle, is the easiest way to centralize it vertically. A convenient +feature is that you can reset the \verb|\arraystretch| and the brace is +still the right size to cover three rows. This example is also set in +a minipage but the footnote markers have been reset as numeric. Follow +DEK's advice: \emph{don't use footnotes in text.} + +% The table in the book is column-width, sans-serif with the heading bold. +\begin{center} +\begin{minipage}{85mm} +\small +\sffamily % choose font +\renewcommand{\footnoterule}{\rule{0pt}{0pt} \vspace{0pt}} +\renewcommand{\thempfootnote}{\arabic{mpfootnote}} +\renewcommand{\arraystretch}{1.1} +\begin{tabular*}{85mm}{@{}l@{\extracolsep{\fill}}r@{\extracolsep{2em}}r@{}} +\noalign{\bf % bold font for whole heading +\begin{tabbing} +Table 3\quad \= Entrants to Youth Opportunities\\ + \> Programme in Wales: by type of\\ + \> scheme +\end{tabbing}}\\ +\multicolumn{3}{l}\textit{Wales 1978 to 1980\hfill Percentages}\\ +\hline + & 1978/79 & 1979/80\\ +\cline{2-2} \cline{3-3} +\noalign{\vspace{3pt}} +WEEP\footnote{Work Experience on Employers' Premises} + & 89 & 73\\ +Short Training Course & 10 & 10\\ +Community Service & & 9\\ +Project based work experience & & 7\\ +Training Workshops &\raisebox{0pt}[0pt][0pt]{% Centre brace +\(\begin{array}{lr} +\left. % null delimiter to match brace +\begin{array}{@{\extracolsep{0pt}}l}\strut \\ \strut \\ \strut \end{array} +\right\} % the big brace +\end{array}\)} 1 & 1\\ +Induction and other\footnote{Employment induction courses and +other remedial and preparatory courses} + & & 1\\ +\noalign{\vspace{3pt}} +\hline +\noalign{\vspace{3pt}} +Total (100\%) & 15,000 & 22,000\\ +\noalign{\vspace{3pt}} +\hline +\end{tabular*} +\end{minipage}%end of \sf default +\end{center} + +The table has a large gap between columns 1 and 2, making it difficult +to see at a glance whether the brace includes `Community Service'. The +original rubric (\cite{msc}) was: +\begin{quote} +``One of the major aims in 1979/80 was to increase the range of provision +available to meet the varying needs of unemployed young people. In the +early days of the Programme, there was heavy reliance on the Work +Experience on Employers' Premises (WEEP) element, but the table reflects +the increasing provision that has now been made in the other elements of +YOP.'' +\end{quote} +As presented, the first impression is that the number of schemes +apparently grew, but each scheme attracted only a small percentage. `1' +as a rounded value is very uninformative, especially as the compared +figures are about 10 and 80\%. There is also a wide gap between the +caption `(100\%)' and the figures it refers to. A quick sum shows that +the numbers entering WEEP went \textit{up} by 20\% between the two periods. +It's a classic political table; you can fiddle it to either praise or +condemn. + + +\begin{thebibliography}{99} +\frenchspacing +\bibitem[Chapman 1986]{chapman}{Chapman M. \& B. Mahon (1986)\textit{Plain Figures}. +HMSO} +\bibitem[Ehrenberg 1981]{ehrena}{Ehrenberg A.S.C. (1981) \textit{The Problem of Numeracy}. +The American Statistician, Vol 35, No 2} +\bibitem[Ehrenberg 1978]{ehrenb}{Ehrenberg A.S.C. (1978) \textit{Data Reduction: Analysing +and Interpreting Statistical Data}. John Wiley} +\bibitem[CSO 1988]{key}{Central Statistical Office (1988) \textit{Key Data 88}. HMSO London} +\bibitem[Kopka \& Daly 1993]{kopka}{Kopka H. \& P.W. Daly (1993) \textit{A Guide to \LaTeX}. +Addison-Wesley} +\bibitem[Kroonenberg 1994]{Kroo}{Kroonenberg S. (1994) \textit{Table Design}. Baskerville +Vol.\ ~4 No.\ ~4 (reprint of article from NTG journal)} +\bibitem[Lamport 1986]{lamport}{Lamport L. (1986,1994) \textit{\LaTeX: User's Guide}. +Addison-Wesley} +\bibitem[MSC 1979/80]{msc}{Manpower Services Commission \textit{Annual Report 1979/80}, +para~8.34 and Table~35. HMSO} +\bibitem[Reese forthcoming]{reesettn}{Reese R.A. \textit{Dividing a Table Alphabetically}, +submitted to TTN} +\bibitem[Reynolds 1983]{reynolds}{Reynolds, L. (1983) \textit{Presentation of Data in +Science}. Nijhoff, The Hague} +\bibitem[Thibault et al. 1993]{thibault}{Thibault J.-C., Vigne J.-D. \& J. Torre (1993) {\it +The Diet of young Lammergeiers in Corsica}. Ibis Vol.~135 No.~1} +\bibitem[Townsend 1970]{townsend}{Townsend R. (1970) \textit{Up the Organization}. +Michael Joseph, London (Coronet edition 1971)} +\bibitem[Tufte 1983]{visdis}{Tufte, E. (1983) \textit{The Visual Display of +Quantitative Information}. Graphic Press, Conn} + +\end{thebibliography} + +\end{Article} |