Academic sentences are often lengthy. They make a point and then add multiple caveats and embellishments.

Some people think there is an ideal sentence length. I have read for instance that the ideal newspaper sentence is somewhere around twenty words. Perhaps a little more, perhaps a little less. But around the twenty word mark.

I’ve also read that many academic sentences surpass this target by rather a lot. The academic sentence can go up to sixty, even seventy words without flinching. Believe it. Just try this one on for size.

While ghosts appear to wield considerable power – including in Derrida’s (1994) account, which ascribes to them the intimidating visor effect (the ability to see without being seen) as well as the ability to put time out of joint and hand down injunctions – their dependency on being acknowledged by the living ensures that they are never all powerful.

That’s 56 words excluding date.

But when you read this sentence it’s not impossible to understand. It’s a bit clumsy, yes, but you can probably see what it’s getting at. Its length doesn’t even seem particularly excessive. Our lack of surprise at the sentence length is probably a sign that we academics are VERY used to reading long.

But don’t imagine that it’s just the social sciences that use lots of words per sentence.

Psychotherapy researchers who realise that the effect of the therapy to which they are allied is less beneficial than another therapy cannot easily switch their research programme to another therapy (since they have often been trained in that therapy for many years), in contrast with a researcher addressing pharmacotherapy who can more easily change his or her research agenda to another drug if a drug proves to be less effective than previously thought.

There are 73 medical words here. And it too is comprehensible- although only just IMHO.

Very long sentences can be quite tricky for readers – even long-sentence-innoculated academic readers – to navigate. Too many additional thoughts all at once and the reader loses the will to go on. They get confused and can’t remember the main point they are meant to be following.

This is not a reason to write nothing but short sentences. Academic writers can reasonably expect colleagues, other academic readers, to stay upright at the occasional encounter with a lengthy bit of syntax. They/we won’t rub their/our eyes and nod off at their desks, even though they/we might sigh a bit if the sentence is really, well, too long.

The reader-asleep problem really arises when the text is nothing but long sentences, Seventy words followed by another seventy words, followed by…  Long sentences, one after another, like a never-ending series of canal step locks. Hello Caen Hill. Half way through and it’s time for a cup of tea.

But actually, long sentences are not the only source of reader enervation. Too many short sentences have exactly the same zzzz-inducing effect. Miles of short sentences feel as if you’re reading a particularly shoddy newspaper or a primary school essay, not a serious scholarly work. Equally tiring and tiresome.

So if length per se is not the problem, what is? Well dear reader, it’s repetition, the lack of variation.

To keep readers awake you need to not only vary your sentence structure, but also your sentence length. Some long sentences, some medium, some short – the Goldilocks principle. It’s not so hard to do. Here’s an example of sentence variation where the long and short are used to good effect.

Communication between doctors and patients is a core component of patient experience. Patients’ evaluations of doctors’ interpersonal skills are widely used in assessments of the quality of care, with an increasing focus on the public reporting of patient feedback. In the USA and the UK, certain minority ethnic groups report lower patient experience scores compared to the majority population. For example, analysis of the English General Practice Patient Survey found that South Asian groups report particularly low scores compared to the White British majority, with Bangladeshi and Pakistani groups providing the lowest scores. Around half of the difference in these scores is explained by the concentration of South Asian patients in low-scoring primary care practices. The remaining difference currently remains unexplained.

The first sentence is 12 words – it’s quite short and its job is to state what is coming up in the  paragraph. The second is 27 words and establishes two connected points about the topic of the paragraph – patient evaluation and public reporting. A key factual focussing point then takes only 21 words. The fourth sentence is 34 words long and adds important evidential detail to the paragraph topic. The fifth and penultimate sentence is 22 words long and adds one more key additional point. The final sentence, which is actually the warrant for the particular study being reported, is a mere snippet at six assertive words.

You can see in this paragraph the varation in sentence length, as well as the reasons for the syntactical length choices made. Long sentences can provide evidence, qualifying information and nuance. Short sentences offer the opportunity to emphasise a particular point  – the crunch. They provide a concise summary of what is to come. They can also – although not apparent in the example above  – pile up point after point before the writer moves onto a summary.

As readers, we are often not aware of differences in sentence length. But we certainly feel the lack of variety. If all that the writer offers is a steady diet of similarly worded sentences, we experience the reading as being ‘hard going’. As a result, we may just give up, at least for a bit.

Sentences that don’t do their job as well as they might  are sentences that communicate their information poorly. The result is that the overall sense, the writer’s argument, doesn’t work as well as it might. Poorly structured and repetitive sentences can leave  a reader incredulous and unconvinced as well as unable to keep track.  Form and function are one when it comes to academic writing (well, in any writing to be fair).

We usually describe the ways in which sentence length is handled as rhythm. The term rhythm draws attention to the soporific nature of monotony, the counting sheep effect of similar length sentences one after another. But this is not all that is involved in repetitive writing. It is important not to lose sight of the ways in which the points we are making – the function of each and every sentence – are linked to their length. We don’t just vary sentences any-old-how. We choose different sentence lengths to do different kinds of work. Our sentence word budget fits the job it has to do.

Keeping readers awake means that we have to pay attention to the structure, meaning and rhythm of the writing. To keep readers awake we need to vary the number of words we use, and how we use them, in keeping with the work being done in the sentence and in the overall sequence.