Empty frame due to `allowframebreaks`

Question

The MWE below, after compiling with pdflatex mwe.tex && bibtex mwe.aux && pdflatex mwe.tex generates a PDF with 3 pages. 1. the sigh frame, 2. the first of two bibliography frames, and finally a contentless "Bibliography II" frame (i.e. empty page/empty frame).

I am aware that allowframebreaks is a terrible idea for actual content and might have is flaws but in this case I'd like to use it nevertheless. What's the reason for the empty frame and how to avoid it (apart from changing the content of the bibliography of course ;)?

\documentclass{beamer}
\usepackage[utf8]{inputenc}
\title{}
\author{}
\date{\today}
\bibliographystyle{IEEEtran}

\usepackage{filecontents}

\begin{filecontents*}{bib.bib}
@article{bornmann2017,
  author="Bornmann, Lutz",
  title="Measuring impact in research evaluations: a thorough discussion of methods for, effects of and problems with impact measurements",
  journal="Higher Education",
  year="2017",
  month=may,
  day="1",
  volume="73",
  number="5",
  pages="775--787",
  issn="1573-174X",
  doi="10.1007/s10734-016-9995-x",
}

@article{meyer2009,
  author = {Meyer, Bertrand and Choppy, Christine and Staunstrup, J{\o}rgen and van Leeuwen, Jan},
  title = {Viewpoint: Research Evaluation for Computer Science},
  journal = {Communications of the ACM},
  volume = {52},
  number = {4},
  month = apr,
  year = {2009},
  issn = {0001-0782},
  pages = {31--34},
  numpages = {4},
  doi = {10.1145/1498765.1498780},
  acmid = {1498780},
  publisher = {ACM},
  address = {New York, NY, USA},
}

@techreport{esposito2018,
  author = {Floriana Esposito and Carlo Ghezzi and Manuel Hermenegildo and Helene Kirchner and Luke Ong},
  title = {Informatics Research Evaluation},
  institution = {Informatics Europe Informatics Europe Informatics Europe Informatics Europe Informatics Europe Informatics Europe Informatics Europe Informatics Europe Informatics Europe Informatics Europe Informatics Europe},
  day = {22},
  month = mar,
  year = {2018},
  url = {http://www.informatics-europe.org/component/phocadownload/},
}
\end{filecontents*}

\begin{document}

\begin{frame}{sigh}
  \cite{*}
\end{frame}

\begin{frame}[c,allowframebreaks]{Bibliography}
  \bibliography{bib}
\end{frame}

\end{document}

I forgot to mention that I tried playing with the factor of allowframebreaks and this can be more or less used as a workaround but since it has to be customized for each case I'd still like to know what triggers it and if a fix is feasible.

I really hope this is not as embarrassing as the previous version of this question (not mine! ;)

Answer 1

I think the problem is that you are instructing the framebreak to happen earlier than usual by setting allowframebreaks=0.85. In your case this means that the framebreak is supposed to be somewhere within the 3 bib entry, but bib entries cannot be split across slides.

2 workarounds:

Use the whole frame with allowframebreaks or make the framebreak before the third item, e.g.allowframebreaks=0.75

\documentclass[a4paper]{beamer}
\usepackage[utf8]{inputenc}
\title{}
\author{}
\date{\today}
\bibliographystyle{IEEEtran}

\usepackage{filecontents}

\begin{filecontents*}{bib.bib}
@article{bornmann2017,
  author="Bornmann, Lutz",
  title="Measuring impact in research evaluations: a thorough discussion of methods for, effects of and problems with impact measurements",
  journal="Higher Education",
  year="2017",
  month=may,
  day="1",
  volume="73",
  number="5",
  pages="775--787",
  issn="1573-174X",
  doi="10.1007/s10734-016-9995-x",
}

@article{meyer2009,
  author = {Meyer, Bertrand and Choppy, Christine and Staunstrup, J{\o}rgen and van Leeuwen, Jan},
  title = {Viewpoint: Research Evaluation for Computer Science},
  journal = {Communications of the ACM},
  volume = {52},
  number = {4},
  month = apr,
  year = {2009},
  issn = {0001-0782},
  pages = {31--34},
  numpages = {4},
  doi = {10.1145/1498765.1498780},
  acmid = {1498780},
  publisher = {ACM},
  address = {New York, NY, USA},
}

@techreport{esposito2018,
  author = {Floriana Esposito and Carlo Ghezzi and Manuel Hermenegildo and Helene Kirchner and Luke Ong},
  title = {Informatics Research Evaluation},
  institution = {Informatics Europe Informatics Europe Informatics Europe Informatics Europe Informatics Europe},
  day = {22},
  month = mar,
  year = {2018},
  url = {http://www.informatics-europe.org/component/phocadownload/},
}
\end{filecontents*}

\begin{document}

\begin{frame}{sigh}
  \cite{*}
\end{frame}

\begin{frame}[c,allowframebreaks]{Bibliography}
  \bibliography{bib}
\end{frame}

\begin{frame}[c,allowframebreaks=0.75]{Bibliography}
  \bibliography{bib}
\end{frame}


\end{document}