Scientific writing 3.0: A reader and writer's guide - Jean-Luc Lebrun, Justin Lebrun 2021

Topic to sub-topic progression
Set progression tracks for fluid reading
The reading toolkit

In this progression, the main topic is usually announced in the first sentence, and subsequent sentences examine aspects of the topic. In the following example, the first sentence is about visuals. The next two sentences review two aspects of visuals: their placement, and their convincing power.

Visuals are star witnesses standing in the witness-box to convince a jury of readers of the worth of your contribution. Their placement in your paper is as critical as the timing lawyers choose to bring in their key witness. But most of all, their convincing power is far beyond that of text exhibits.

Chain progression

In a chain progression, topic and stress are daisy-chained. The stress at the end of a sentence becomes the topic at the beginning of the next sentence. This frequently used progression scheme is easy for readers to follow. It is illustrated in the next paragraph.

“The Brownian motion of the protein strand will carry it willy-nilly between various shapes, somehow finally getting it to settle down into a much less diverse family of shapes, which we call the “native structure” of the protein. The average native structures of many proteins have been inferred experimentally using X-ray crystallography or NMR.”²

The elements in a daisy chain do not need to be repeated word for word from one sentence to the next. Often, the verb in a previous sentence becomes a noun at the head of the next sentence.

Applying Kalman filters reduced the noise in the data sent by the lowcost ultrasonic motion sensors. The reduction was sufficient to bring down the detection error rate below 15%.

Sometimes, part of the previous sentence (bolded in the following paragraph) is brought forward in the next sentence by way of a pronoun such as ’This’.

“The above observations can be generalized to a rather important conclusion. If large mole differences between species exist in a data set (and this is often the normal case for catalytic reactions), then the reactions involving both major and minor species should be rewritten to include only the latter. This should solve the problem of abnormal gradients in the extent of reactions for most cases.”³

Don’t fall in love with this paragraph though. It has its problems. It could be more concise: the rather in ’rather important’ is unnecessary. It also contains a wonderful example of an ambiguous pronoun in the last sentence. What does ’This’ represent? If you answer ’the reactions,’ read the sentence again because it is not the correct answer. ’This’ refers to the rewriting.

Figure 1

Three topic-based progression schemes. A sentence is represented by a rectangle; its topic by an object at the head of the sentence. In the chain progression, the topic retains the same shape as the previous stress to indicate that the stress of one sentence becomes the topic of the next sentence.

Each of the three topic-progression schemes (Fig. 1) influences expectations and vice versa.

The constant topic progression answers the need to know more about the same topic (expectation of elaboration — breadth). The topic/subtopic progression answers the need to go deeper into the topic (expectation of elaboration — depth). The linear progression answers the need to see how things are related (expectations of relatedness and outcome). Going back to our metaphor of text as train tracks, the constant topic is the simplest scenario: the train continues in a straight line with no deviations. The topic-to-subtopic scenario takes the main train of thought on a sidetrack parallel to the main track. And the chain progression takes the train away from the main track to new destinations.

Topic-based progression schemes are complemented by schemes that do not depend on the topic.