Reviews

How to write a nature-style review

Nature Reviews Neuroscience is one of the foremost journals in neuroscience. What do its articles look like? How have they developed? This blog post provides answers which might guide you in writing your own reviews.

Read more than you used to

Reviews in Nature Reviews Neuroscience cover more and more ground. Ten years ago, 93 references were the norm. Now, reviews average 150 references. This might be an example of scientific reports in general having to contain more and more information so as not to be labelled ‘premature’, ‘incomplete’, or ‘insufficient’ (Vale, 2015).

nrn_fig1

Reviews in NRN include more and more references.

Concentrate on the most recent literature

Nature Reviews Neuroscience is not the outlet for your history of neuroscience review. Only 22% of cited articles are more than 10 years old. A full 17% of cited articles were published a mere two years prior to the review being published, i.e. something like one year before the first draft of the review reached Nature Reviews Neuroscience (assuming a fast review process of 1 year).

nrn_fig2

Focus on recent findings. Ignore historical contexts.

If at all, give a historical background early on in your review.

References are given in order of first presentation in Nature Reviews Neuroscience. Dividing this order in quarters allows us to reveal the age distribution of references in the quarter of the review where they are first mentioned. As can be seen in the figure below, the pressure for recency is less severe in the first quarter of your review. It increases thereafter. So, if you want to take a risk and provide a historical context to your review, do so early on.

nrn_fig3

Ignore historical contexts, especially later in your review. Q = quarter in which reference first mentioned

The change in reference age distributions of the different quarters of reviews is not easily visible. Therefore, I fit a logarithmic model to the distributions (notice dotted line in Figure above) and used its parameter estimates as a representation of how ‘historical’ references are. Of course, the average reference is not historical, hence the negative values. But notice how the parameter estimates become more negative in progressive quarters of the reviews: history belongs at the beginning of a review.

nrn_fig4

Ignore historical contexts, especially later in your review: the modeling outcome.

Now, find a topic and write that Nature Review Neuroscience review. What are you waiting for?

— — —

Vale, R. (2015). Accelerating scientific publication in biology Proceedings of the National Academy of Sciences, 112 (44), 13439-13446 DOI: 10.1073/pnas.1511912112

— — —

All the R-code, including the R-markdown script used to generate this blog post, is available at https://github.com/rikunert/NRNweb

Neuroscience is Forgetting

The scientific enterprise, like anything else humans are doing, is subject to fashions, trends and hypes. Old ideas get replaced by new ones; good new ideas spread; progress is made. However, is Neuroscience forgetting where it came from?

This is not that hard to investigate in a quantitative way because every source that is cited by an article is referenced. Below, I plot the ages of all references found in reviews and review-like articles (opinions, perspectives…) published in a well known Neuroscience journal (Nature Reviews Neuroscience). As you can see, the relative majority of articles which a review cites are very very recent, i.e. less than two years old. Twenty year old sources hardly every get mentioned.
Forgetting Rate in Nature Reviews Neuroscience
One could argue that the pattern seen above – the very fast rate of decline which levels off near zero – is simply a reflection of the publication rate in Neuroscience. If more is published, more can get referenced. However, compare the above plot with the one below, which shows the publication rate in the Neurosciences from 2011 all the way back to 1975. An increase in publication rate is there but it is not nearly as quick as the aforementioned graph would have you believe.
Neuroscience Publication Rate
Something else is happening.
Notice the white bars in Figure 2. These show the overall number of reviews in Neuroscience. While in 1975 only 46 Neuroscience reviews got published, in 2011 it was nearly 3000. Given that it is impossible to read anything like 40000 original articles each year, it makes sense to only read the summaries. Perhaps, once summarised, an original article’s gist survives in the form of a brief mention in a review while its details are simply forgotten.
Another possibility is the decline effect I blogged about before. Old articles which proved unreliable should be forgotten in order to edge closer to some scientific truth. They may have suffered from publication bias, sub-optimal techniques and/or sampling bias.
So, Neuroscience is indeed forgetting. However, whether this is all that bad is another question.

——————————————————————————————

Figures:
1) Data processed with own code. Original data from NRN website.
2) Data from Web of Science.