# “et al.” for 3 or more authors, not 4 or more, authors in a citation call-out with “aea” bibliography style

I'm using the AEA template with natbib. I want to have citations with 3 authors show "FirstAuthor et al." instead of all 3 authors' names. (The bibliography style uses the "et al." truncation automatically if a publication has four or more authors.)

I believe that a change needs to be made in the change_AEA.bst file in this section (but am unsure of what/how to change):

FUNCTION {format.names.label}
{ 's :=
#1 'nameptr :=
s num.names$'numnames := numnames 'namesleft := { namesleft #0 > } { s nameptr "{ff }{vv~}{ll}{, jj}" format.name$ 't :=
nameptr #1 >
{ namesleft #1 >
{ ", " * t * }
{ t "others" =
{ " et~al." * }
{ " \harvardand\ " * t * }
if$} if$
}
't
if$nameptr #1 + 'nameptr := namesleft #1 - 'namesleft := } while$
}


I believe the original .bst file can be found here: https://www.aeaweb.org/journals/policies/templates

• Welcome to TeX.SX. The journal will ignore any changes you make to the format. Don't bother. – Johannes_B Nov 16 '19 at 13:41
• Changes should still work for internal use though (which is what I need it for). – Metrics Master Nov 16 '19 at 13:44

Echoing the sentiment expressed by @Johannes_B, I don't think it's a good idea to modify the file aea.bst. In my opinion, the only valid reason for using this particular bibliography style is if you're planning to submit a paper either to the American Economic Review or to one of its sister publications.

However, if you really, absolutely, must change the cutoff threshold for using et al in citation call-outs, I suggest you proceed as follows:

• Make a copy of the file aea.bst and call the copy, say, aeamod.bst. (Don't modify the file aea.bst directly).

• Open the file aeamod.bst in a text editor. The editor you use for the your tex files is fine.

• In aeamod.bst, search for the BibTeX function called format.names.label.short. (It starts on line 572 in my copy of the file.)

• In this function, locate the line

  numnames #3 >


Change it to

  numnames #2 >

• Save the file aeamod.bst either in the directory where your main tex file is located or in a directory that's searched by BibTeX. If you choose the latter option, be sure to update the filename database of your TeX distribution suitably.

• In your main tex file, change the instruction

\bibliographystyle{aea}


to

\bibliographystyle{aeamod}


and run a full recompile sequence -- LaTeX, BibTeX, and LaTeX twice more -- to propagate the effects of the change you made to the bibliography style file.

Happy BibTeXing!

A full MWE (minimum working example) and its output:

\documentclass{article}

\begin{filecontents}[overwrite]{mybib.bib}
@misc{ab,author="Albertson, Angela and Bronson, Bronwyn",title="Thoughts",year=3000}
@misc{abc,author="Angela Albertson and Bronwyn Bronson and Cristina Christensen",title="Thoughts",year=3001}
@misc{abcd,author="Angela Albertson and Bronwyn Bronson and Cristina Christensen and Darla Drorsen", title="Thoughts",year=3001}
\end{filecontents}

\usepackage{har2nat}
\bibliographystyle{aeamod}

\begin{document}
\cite{ab}

\cite{abc}

\cite{abcd}

\bibliography{mybib}
\end{document}