The Information to Authors page states the following.

• 6. TODS will discourage excessively long papers (longer than 50 double-spaced pages including figures, references, etc.), and unnecessary digressions even in shorter papers. This is to motivate the authors to bring out the essence of their papers more clearly, to make it easier for the reviewers and readers, and to allow TODS to publish more papers in any given issue.
• 7. In a similar vein, TODS encourages shorter submissions, including even very short (say, five page) submissions. The primary criterion for acceptance is improving on the state-of-the-art in some significant way."

In comparison, in 1976 (volume 1), the average paper was 19.2 pages long, and the longest was 41 pages (!!)

It is important to keep working to get papers down to a more manageable length. Readers nowadays are reticent to wade through long articles. Reviewers are also reticent to carefully study long submissions.

The general approach of this policy is to gradually move submissions towards the final paper we would like to see.

• The policy of 50 double-spaced pages for submissions is retained. The EiC will continue to be flexible with regard to what double-spaced means (in LaTeX, double spacing really generates 1.5 spacing), and also will allow appendices beyond the 50 page limit.
• For papers that pass the first hurdle, that is, are not rejected after the first review, the associate editor will request that the revision be formatted according to TODS format, with a body (paper plus references, but without appendices) no longer than 45 pages, with most papers given a tighter limit, based on the AE's sense for the core contribution of the paper. Remaining material can be in one or more appendices, without a page restriction. The AE will make this reduction of the core be a requirement for the revision
• When the paper is accepted, the acceptance email from the AE will state that both the core of the paper (including bibliography) and the appendix will appear in the ACM DL, but that only the core of the paper will appear in the print copy, with a pointer to the electronic appendix. Examples from the March 2004 issue include
  • Torsten Grust's paper, which has a four page electronic appendix
  • Peter Buneman's paper, which has an 11-page electronic appendix,
  • Jennifer Widom's paper, which has a 13-page EA, and
  • Marcelo Arenas's paper, which has a 7-page EA.
  This will be a requirement for acceptance of the paper.
• The maximum paper length will thus be reduced to 45 pages, with most papers around 25-30 pages long, through aggressive use of electronic appendices. This will help reduce the average paper length, towards an eventual goal of 33 pages. Electronic appendices will be of unbounded length, allowing for thorough exposition of the material, in an economically-feasible way.
• The ACM citation page affords the opportunity to provide access through the ACM Digital Library to related materials such as technical reports, experimental results, and source code. For each paper with relevant associated material, either the material is added directly to the citation page, or a link will be added to a separate page providing additional material and links, depending on the authors' preference. It is important to note that these materials and additional links are different than an electronic appendix, in that the latter is refereed and the former is not.

On October 15, 2005 the first sentence of item 6 of the Editorial Guidelines, which now reads

TODS will discourage excessively long papers (longer than 50 double-spaced pages including figures, references, etc.), and unnecessary digressions even in shorter papers.

TODS will discourage excessively long papers (longer than 50 double-spaced pages---or 50 pages in TODS format---including figures, references, etc. but not including any appendices), and unnecessary digressions even in shorter papers.

The following two sentences were added to "How to Prepare Final Version" of the Information for Authors public page.

The final version of the paper can be no longer than 45 pages in ACM format. Additional material can be placed in an electronic appendix, for which there is no a priori length restriction.