How Long Should the Discussion Section Be? Data from 61,517 Examples

I analyzed a random sample of 61,517 full-text research papers, uploaded to PubMed Central between the years 2016 and 2021, in order to answer the questions:

What is the typical length of a discussion section? and which factors influence it?

I used the BioC API to download the data (see the References section below).

Here’s a summary of the key findings

1. The median discussion section was 1,115 words long (equivalent to 43 sentences, or 7 paragraphs), and 90% of the discussion sections were between 482 and 2,230 words.

2. Compared to other sections in a research paper, the discussion was about the same length as either the methods or the results, and double the length of the introduction.

3. The length of the discussion does not differ between review articles and original research articles.

4. The quality of the journal does not influence the length of the discussion section.

Overall length of the discussion section

Here’s a table that describes the length of a discussion section in terms of words, sentences, and paragraphs:

Discussion Section Length
Word CountSentence CountParagraph Count
Minimum40 words1 sentence1 paragraph
25th Percentile824 words32 sentences5 paragraphs
50th Percentile (Median)1,115 words43 sentences7 paragraphs
Mean1,206.8 words46.4 sentences7.8 paragraphs
75th Percentile1,480 words57 sentences9 paragraphs
Maximum32,816 words2,006 sentences981 paragraphs

From these data, we can conclude that the discussion sections in most research papers are between 824 and 1,480 words long (32 to 57 sentences).

If you are interested, here are the links to the articles with the shortest and longest discussion sections.

The discussion section constitutes 29.5% of the total word count in a research article, equivalent to the length of either the methods or the results, and double the length of the introduction [source: How Long Should a Research Paper Be?].

Length of the discussion for different article types

The following table shows the median word count of the discussion section for different study designs:

Study designNumber of studies in the sampleMedian discussion word count
Case series140 studies1,003 words
Case-control443 studies1,016 words
Randomized controlled trial842 studies1,066 words
Case report407 studies1,077 words
Meta-analysis1,481 studies1,116 words
Quasi-experiment144 studies1,117 words
Cross-sectional3,529 studies1,128 words
Cohort5,180 studies1,164 words
Pilot study686 studies1,185 words
Systematic review689 studies1,210 words

The data show no clear pattern since the discussions of review articles and original research articles have almost similar word counts. So we can conclude that there is no particular article type that requires a longer discussion section.

Length of the discussion in different journals

In order to study the influence of the journal quality on the length of the discussion section, I ran a Poisson regression that models the discussion word count given the journal impact factor. Here’s the model output:

VariablesCoefficientStandard errorp-value
Journal impact factor0.001<0.001<0.001

The model shows that a higher journal impact factor is associated with a slightly longer discussion section. Although statistically significant, this effect is practically negligible since a 1 unit increase in the journal impact factor is associated with an increase of only 0.1% in the discussion word count. For the median article, this means that a 1 unit increase in the journal impact factor is associated with an approximate increase of 1 word in the discussion section.


  • Comeau DC, Wei CH, Islamaj Doğan R, and Lu Z. PMC text mining subset in BioC: about 3 million full text articles and growing, Bioinformatics, btz070, 2019.

Further reading