How to format tables with multiline cell values by incorporating word wrap?

Question

I am trying to make a table with multiline values in a cell. Following is the MWE:

\documentclass[12pt]{article}
\usepackage[a4paper, total={170mm,262mm}, left=20mm, top=20mm]{geometry}
\usepackage{booktabs}
\usepackage{multirow}

\pagestyle{empty}

\begin{document}

\begin{table}[ht]
\centering
\caption{Studies that made a quantitative estimate of the parameters for the analysis on the blah blah blah blah}
\begin{tabular}{p{3.8cm}p{2cm}p{4cm}p{5cm}}
\hline
 {\bf Study} & {\bf Study} & {\bf Lead time}  & {\bf Methodology for}\\
{\bf location} & {\bf Period} & {\bf (days)} &  {\bf qualifying lead time.}\\
\hline 
City 1, Country 1 & Jun--Aug 2020 & 2 & \textit{Method 1}: attribute 1 vs attribute 2 \\
City 2, Country 2 (detail A, detail b) & Aug 2020--Jan 2021 &
0 to 6 (different sublocations) & \textit{Method 2}: attribute 1 vs attribute 2 given a certain preprocessing (7-day) \\
\hline
\end{tabular}
\end{table}

\end{document}

The output has issues and is as follows:

Instead of the above, I want to obtain a neat-looking table with the following features:

1. Table spanning the text (line) width
2. Reasonable spacing between the table caption and the body
3. Word wrapping wherever the content goes beyond column width (including the table headers).
4. First column: I want the city and the country in separate lines. If there is additional text, it should come further below with word wrapping.
5. Left justification for everything (I am okay if we have centre-justified column headers)
6. No underfull/overfull warnings
7. Sufficient space between the rows (The above table looks bad if we add more rows)

An example of a desirable table (generated in MS-Word), but without caption, looks like this:

Can anyone suggest how to get such a table?

Answer 1

Your requirements can be easy fulfil by use of the tabularray and booktabs packages:

\documentclass[12pt]{article}
\usepackage[showframe,          % in real document remove this option
            a4paper, total={170mm,262mm}, left=20mm, top=20mm]{geometry}
\usepackage{tabularray}         % new
\UseTblrLibrary{booktabs}       % booktabs package load as  tabularray library
\usepackage[skip=1ex,
            font=small,
            labelfont=bf]{caption}  % for caption formating

\begin{document}
    \begin{table}[ht]
\caption{Studies that made a quantitative estimate of the parameters for the analysis on the blah blah blah blah}
\begin{tblr}{colspec = {@{} X[1.8, l] X[2, l] X[2, l] X[2.5,l] @{}},
             rowsep=5pt,
             row{1}  = {font=\bfseries,rowsep=2pt},
             }
    \toprule
{Study\\  location}
    &   {Study\\ Period}
        &   {Lead time\\ days}   
            &   {Methodology for\\ qualifying lead time.}   \\
    \midrule
{City 1,\\ Country 1}
    & Jun--Aug 2020 
        & 2 & \textit{Method 1}: attribute 1 vs attribute 2 \\
{City 2,\\ Country 2\\ 
(detail A, detail b)}
    & Aug 2020--Jan 2021 
        & 0 to 6 (different sublocations) 
            & \textit{Method 2}: attribute 1 vs attribute 2 given a certain preprocessing (7-day) \\
    \bottomrule
\end{tblr}
    \end{table}
\end{document}

Answer 2

Here's a solution that employs a tabularx environment (with a target width of \textwidth) and a variable-width version of the X column type for all four columns. Do also note (a) the judicious use of \newline directives to create line breaks within cells and (b) the use of \addlinespace to insert whitespace between rows.

\documentclass[12pt]{article}
\usepackage[a4paper, total={170mm,262mm}, left=20mm, top=20mm]{geometry}
\usepackage{booktabs}
% \usepackage{multirow} % (not needed)

% new code:
\usepackage[skip=0.333\baselineskip]{caption} % space below caption
\usepackage{tabularx} % for 'tabularx' env. and 'X' column type
\newcolumntype{L}[1]{%
  >{\raggedright\arraybackslash\hsize=#1\hsize}X}
\usepackage{newtxtext,newtxmath} % optional (Times Roman font clones)

\pagestyle{empty} % why?

\begin{document}

\begin{table}[htbp]

\caption{Studies that made a quantitative estimate of the parameters for the analysis on the blah blah blah blah}
\begin{tabularx}{\textwidth}{@{} L{0.8}L{0.6}L{0.9}L{1.7} @{}} % 0.8+0.6+0.9+1.7 = 4 = # of X-type columns
\toprule
\bfseries Study location & \bfseries Study Period & \bfseries Lead time, in days & \bfseries Methodology for qualifying lead time\\
\midrule
City 1, \newline Country 1 & Jun--Aug 2020 & 2 & \textit{Method 1}: Attribute 1 vs attribute 2 \\
\addlinespace
City 2, \newline Country 2 \newline (detail A, detail B) & Aug 2020--\hspace{0pt}Jan 2021 &
0 to 6 (various sublocations) & \textit{Method 2}: Attribute 1 vs attribute 2 given a certain preprocessing (7-day) \\
\bottomrule
\end{tabularx}
\end{table}

\end{document}