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January 2019

Six patterns of explanation

People-3d-thinking-mind-mapping-497747340-5b31bbec8e1b6e0036ab2793[image: DrAfter123 / Getty Images]

We understand information by pattern-matching. If you can organise information into a simple pattern that your audience or reader can recognise, they'll be better prepared to understand it.

For instance, we can explain in six different ways. I have no idea who first created this list of patterns, but my hunch is that it appeared at some point in the early nineteenth century. The list varies slightly from textbook to textbook; this is the version I've found most useful over the years.




Comparison and contrast

Cause and effect

Chronological or process pattern

Get to know these patterns. They'll help you explain anything more clearly.



Explanation by example, probably the simplest pattern, creates a list. Examples can help make an idea concrete by creating a mental image.

Journey times for passengers are just about keeping to expected levels on all Tube lines. The Metropolitan, East London, Northern and Piccadilly all report additional excess journey time averages. The Bakerloo, Victoria and District Lines showed the most marked improvement during the Christmas period. 

Signal words for explanation by example include:

  • in addition
  • another
  • for example
  • also
  • several
  • a number of

This pattern could be presented graphically as a bullet list. (Like the one above!)



We humans seem to have a natural talent for sorting information into categories.  Categories are created by dividing information into parts. This pattern follows three rules.

  • Every item under consideration should fit into one of your categories.  If you have odd items left over, add other categories or rework your existing categories. 
  • Categories should not overlap.
  • Items should fit into only one category.  If you cannot decide where to put something, ask if it can be eliminated as irrelevant, or whether it needs a category to itself.

Give each category a clear name.  Sub-categories will come under larger categories with more general names.

Put things, people, places, into categories based on their similarities. Alternatively, you could take one thing, person, place and divide it into its components.

Make the purpose of classification clear and interesting. A paper classifying the different areas to study in college is not very interesting. A paper classifying the different types of sexism in the classroom is interesting.

Explain how you have created your categories. Include the rule or principle used to classify items into groups. Use examples, details, and data to help readers distinguish between categories.

Playing fields may be owned by private or public landholders. Private owners include companies, banks, sports clubs, developers, or individual land owners not necessarily associated with any commercial enterprise. Public owners include local authorities, schools, colleges or other public sector bodies such as the Civil Service or National Health Service.

Signal words and phrases or categorising include:

  • include
  • exclude
  • not limited to
  • can be divided into
  • types of
  • sorts of

Categorising could be represented graphically by a pie chart.




A definition identifies something uniquely: an object, a procedure, a term or a concept.  There are three types of definition.

  • A short definition explains by means of a synonymous word or phase, often in brackets or between commas. 
  • A sentence definition is made up of two sections: the class to which the object belongs; and the features which distinguish it from all other items in the class.  A glossary is made up of sentence definitions. 
  • An extended definition can be short as a paragraph or as long as a chapter.  It may include a brief history of the term (the language it came from, its current use, how the use has changed).  An extended definition should also include the object's function.

ROI for tourism is the amount of additional visitor expenditure that campaigns generate compared with the amount of public money invested in these campaigns. 

Explore a subject’s meaning fully. Differences within the definition are fine if they exist within the established boundaries.

Draw clear boundaries around the defined subject to avoid confusion with other subjects. Use examples, details, and anecdotes to strengthen your definition.

Signal words and phrases  for definition include:

  • is defined as
  • means
  • is described as
  • is called
  • refers to
  • term
  • concept

I haven't ever found a good visual or graphic representation of definition. A Venn diagram might be helpful. On the other hand:


Comparison and contrast

Comparisons display the similarities between things; contrasts show the differences.  You can use them separately, or together: comparison before contrast.

In our view, the CEE regional businesses share similar growth drivers, in particular robust regional economic outlooks, high growth advertising markets,operational synergies as part of the MTG group,regulatory changes and the launch of niche channels.

The variance in availability of playing fields between inner and outer London is marked. In theory, there are 227 playing fields available to residents in inner London boroughs, as opposed to 1,202 available to residents in outer London.   We discuss availability in theoretical terms because availability does not necessarily equate to accessibility. There are issues around access for local people, who may find themselves deprived of access for a variety of reasons.

The items under consideration must be comparable.  You would not compare the costs of freight haulage by rail in the UK to container haulage to Australia by ship. Establish the criteria by which you are comparing and contrasting.  Have as many as possible: cost, convenience, prestige, size, security, safety and so on. Rank the criteria in priority order.  This might be a controversial exercise, but unless the criteria are weighted you will not be able to contract them effectively.

State a clear purpose regarding why the subjects are being compared or contrasted at the beginning of the paper. Explaining the differences between summer and winter, however well written or spoken, must also be interesting.

Share enough features to make a comparison valuable. Choose a narrow enough basis for comparing or contrasting, so that all major similarities and differences can be covered.

Signal words and phrases for comparison and contrast include:

  • similar, different
  • on the other hand
  • but
  • however
  • bigger than, smaller than
  • in the same way
  • parallel

Comparison and contrast can be presented graphically as a table.

Compare and contrast[image from]


Cause and effect

Cause and effect explains why something happened. 

The difficulty, of course, is in deciding which is cause and which is effect! A cause is so often the effect of another cause, which may be harder to determine or control.  Look for the immediate cause; the underlying cause; and the ultimate cause.  Your analysis will be circumscribed by the areas of responsibility involved.

The breakdown in communications within the London Ambulance service had an impact on the service’s ability effectively to deploy the necessary vehicles, personnel, equipment and supplies to the incidents.  Survivors told us repeatedly of their surprise at the apparent lack of ambulances at the scenes, even an hour or more after the explosions. 

Cause and effect is a technique fraught with danger.  Determine which type of cause you are searching for: immediate, underlying or ultimate.  What is your purpose in identifying these causes?  Be open-minded.  Try not to rush to conclusions or to allocate blame 'politically'.  Be as logical as you can.  Eliminate coincidence.  Take all factors into account.  Is there more than one cause?  Are there other effects that you have not considered?  Trace all the links.  Go as far back as necessary (or as is expedient!) to the ultimate cause.

The robust advertising growth will be largely driven by demand from both local and multinational advertisers, buoyed by deregulation and relatively stable economic conditions.

Signal words for cause and effect explanation include:

  • for this reason
  • consequently
  • as a result
  • on that account
  • hence
  • because

Cause and effect can be represented graphically by a fishbone or Ishikawa diagram. This is also a useful tool for establishing causes of a problem.




Chronological or process pattern

Items are listed in the order in which they occurred or in a specifically planned order in which they must develop.  In this form of explanation, the order is vital; changing it would change the explanation's meaning.

A process pattern lists all the steps necessary to carry out an operation.  It may take the form of a set of instructions (like a recipe), a quality procedure or a technical specification report.  It proceeds step by step.  The steps must occur in a particular order: if the order is wrong, the operation will fail. 

The proposed timetable is as follows:

Scoping brief to Chair on 7 April;

Project Initiation meeting at 10am on 11 April;

Scoping brief to Members on 12 April;

Despatch call for evidence letters by 21 April;

Written evidence received by 26 May;

Evidence analysed and briefing paper prepared for Members by 5 July;

Evidentiary Hearing 13 July;

Formal approval of scrutiny report at 12 October Committee meeting

Process analysis usually tells the reader about a process or how to do it. 

In calculating the cost of capital, we compute the split of earnings between domestic and international operations, which after the deconsolidation of the Argentinean subsidiaries comprise mainly Brazil. To calculate the cost of capital of the domestic operations, we add the eurobond yield of 3.64% to the Italian equity risk premium of 4.0%. To calculate the cost of capital of the international operations, we add the Brazil short term interest rate of 30% to the country risk premium of 6%. Lastly, we calculate the weighted capital obtained on a earnings basis.

Instructions tend to be far more detailed explanations.

Signal words and phrases for chronological or process explanation include:

  • first, second, third
  • first, secondly, thirdly
  • next
  • before
  • after
  • when
  • later
  • until
  • at last

Chronological explanation could be presented graphically as a timetable -

2019_Red_Timetable- or as a timeline:


A set of instructions will be laid out as a numbered list - like a recipe:

RecipeNote that the list of ingredients here is explanation by example. The method is organised as a process. The distinction between the two is made even clearer by the use of bullets for the list of examples, and of numbers for the process. 

Notice also that lists of instructions are not necessarily in process order.


(And please do not try to iron your backside, even on a low heat.)

I run training courses on effective writing email and letter writing, report writing and grammar. Contact me to find out more.



How to submit a proposal for a scicomm presentation


[image via with thanks]

The British Science Association is calling for applications for sessions at the 2019 British Science Festival, to be held in September at the University of Warwick. Maybe you're interested in applying. Maybe you're applying to another sciccomm event somewhere. Maybe you're just starting out planning one. Whatever your interest, these notes will help you hone your application.

We'll go through  a series of six questions. At this stage, you need only simple answers. You’re not planning your presentation yet, only putting together the proposal. If you can be clear about this key elements, your proposal will be more convincing and attractive.


What's your goal?

A recent report from the National Academies of Sciences, Engineering and Medicine in the US suggested that science communicators typically have one or more of these five goals. I see them sitting on a spectrum with 'pure' science at one end and more or less strong social advocacy at the other.

Notice that all five goals relate to your audience - not to your subject. As we move along the spectrum, think about how - and how much - you might want to involve your audience in the presentation.

Sharing the excitement of science

Nothing wrong with that. We can all get far too hung up on relevance and social impact. Science is amazing. Celebrate it.

To increase appreciation for science as a useful way to make sense of the world

Perhaps you're assuming that, once your audience understands more about a subject, they'll be more willing to act on that knowledge. Not an unreasonable assumption, although the NAS report says that it's not yet been fully tested.

To increase understanding of the science related to a specific issue

Similar to the last goal, but in this case, you're tackling a specific issue and trying to educate your audience about the relevant facts. At this point on the spectrum, controversy raises its head - and not just from the audience's side. We're talking here about the 'deficit' model of scicomm, which assumes that “the science” of a controversial issue is settled, that the experts accept it without question and that the task of communication is simply to explain the facts to an ignorant public. Many scientists hold this as a mental model. And, as the report points out, it's false. You want to increase knowledge and understanding of GM foods by simply presenting the facts? You may face resistance.

To influence people’s opinions, behavior, and policy preferences

Moving further along the spectrum, at this point you want to do more than present the facts. You want to influence. You have scientific evidence clearly showing that certain choices or policies have more positive social consequences. You'll need to relate the facts to the audience's priorities, values and beliefs. You need to translate information into ideas, and evidence into meaning. You need to start advocating. And that means, in part, countering misinformation.

To engage with groups from within society, to acknowledge their views on the science of a specific issue, in pursuit of solutions that everyone can accept

Similar to the last goal, but now your audience is more distinctly defined. Maybe you're talking to young people about sexual health; or parents about vaccination; or faith groups about evolution. At this point on the spectrum, your presentation must definitely be part of a dialogue.

Goal wordcloud

Another way of thinking about your purpose is to ask: What do I want my audience to think, feel and do?

  • Think

What do you want the audience to know by the end? What do you want the audience to think about as they leave? How do you want them to think differently about the topic? What’s the ‘aha’ or the ‘so what’? What information or ideas do you want to reinforce – or demolish – in the audience’s mind?

  • Feel

What emotion or response do you want to evoke? What feeling do you most want to associate with your topic? Do you want people to feel hopeful? Angry? Provoked? Confident? Scared? Do you want them to feel motivated, energised or inspired? Presumably you want them to feel entertained throughout – and not baffled or bored. And presentations that deliver unmitigated doom and despair are probably not going to be very motivational.

  • Do

What specific action do you want the audience to take? Do you want them to change their lifestyle? Is there a specific “to-do” or next step? Is there something they need to change? Do they need to demand change from their political representatives, or their employers, or their families? What do you want people to go out and share with others?  The best calls to action are clear and simple.

Think feel do

[Thanks to Linhart PR for some inspiration here – and for the cool image.]

Now focus on the specific rhetorical aim of your presentation. What do you want your presentation to do? My guess is that it will do one of two things.

It will seek either to persuade or to explain.

Persuade explain

Try to pick one - and only one - of those options.

If you think you want to persuade your audience of something, then you will need to construct an argument and then support it in various ways. We can argue in two ways. You'll also need to think about how to persuade using means other than logical argument.

If you think that you want to explain something, then try to decide what type of explanation you want to use. There are six types of explanation.

You can think about all this in more detail later, when you start planning. For now, focus on the key question: persuade or explain?


Who's your audience?

Think about and define your audience as clearly as you can. The festival or organisation you’re proposing to should be able to give you a reasonably clear profile of your audience. The BSA profiles the audience for the British Science Festival as

non-specialist adults (16+) with a broad interest in science

Which is pretty broad. You may have a more specific audience in mind: parents, perhaps; teachers; children; people with a particular need; faith leaders; community leaders; other scientists.

What are likely to be your audience’s preconceptions about the subject you’re presenting? Can you pin down those preconceptions any more tightly than using anecdotal evidence or your own hunches?


What is your message?

We’re aiming here for a single-sentence take-away.What's the 'so what' here?

Imagine an audience member being asked by an outsider as they leave: “What was the key message of that session?” What would you want them to say?

Try to sum up the take-home message of your presentation in a single sentence.


What's the title?

If you are asked for a title, it should be a compressed version of that message. The title should be intriguing and attractive, but it shouldn’t be vague or baffling. Titles are hard. Don’t feel, at this stage, that you have to come up with a brilliant title. Take a look at the titles of the posts on the BSA blog. You could also consider a two-part title. For example:

'You go first': public perceptions of risk in an uncertain world

Who's in the driving seat? managing epilepsy at DVLA

Magic mushrooms: how fungi can save the world


What's your structure?

Remember, at this point you don't need a detailed plan. But you do need a rough idea of the shape of the presentation.

Think about this in two stages.

Divergent thinking first: gather loads of ideas and map them out. Tke your time over this stage, and enjoy it. You can indulge in the luxury of not having to decide on a final structure.



You might want to think about specific types of information. The application form might ask, for example, about the new areas or trends in your area of research; about whether your work is being sponsored by anyone; about any publications or other ways you have promoted your work.

But think also about some of the key elements you'd love to include: any 'wow' moments you might want to deliver, or brilliant examples; images or stories; one-liners that have worked for you in the past.

At some point, transform your divergent thinking into convergent thinking.

Civergent convergent thinking

Look for the end point of the presentation: where do you want your audience to arrive when you finish?

And the start point: where can you imagine your audience standing in relation to this subject at the beginning?

Then think about the journey. How are you going to take the audience from start point to finish point?

Now at this point, as you might imagine, storytelling comes in. But I don't want to get into detail about that - not here.

But let me leave you with just a hint.

The journey is the audience's journey.

Not yours.

Your task is to show the way and help them when the going gets a bit tough.

And at this point we shall take a pause. You’re not required to plan your presentation in detail right now. Your task is to sell it to the festival organisers. The simplest outline of your presentation’s structure is enough. And it’s likely to change as you develop the idea, anyway.


What's the blurb?

You may well be asked for a blurb as part of your application: 50 words that give an impression of the presentation and what it will be like.

This blurb will probably be used for marketing your presentation. Use all your work up to this point to create that 50-word summary. Don’t feel that you must include every element of the structure in that summary; blurbs should entice and intrigue by indicating the questions to be asked or the mystery to be solved – without including the answer or the solution.

Here are some blurbs from recent sessions at the British Science Festival, slightly adapted. They tend to follow predictable patterns.

First, a blurb that begins with a simple statement of fact.

Statistics supply vital evidence to shape public policy. Laura Bonnett has been working to influence DVLA policy on granting licences to drivers who’ve suffered seizures. In the Rosalind Franklin Award Lecture at this year’s British Science Festival, she will take us through the process.


Robots are set to play an increasingly important role in our lives. What is the future of robotics? Greg Toland from Innovate UK will show us a world that's stranger and less frightening than we might think.

Or you might start by simply stating your name and what you're doing.

Dr Emma Yhnell is looking for ways to build brain resilience in people living with Huntington’s using computer games. She explained more in the Charles Darwin Award Lecture at this year’s British Science Festival.

Your blurb might begin with stating a problem.

Detecting brain damage in newborns is notoriously difficult. Gemma Bale of UCL is helping to develop an innovative method for investigating brain activity – using infrared light. Her area of research that promises to give new hope to babies and their families.


Biodiversity is under threat around the planet. Claire Burke is helping to pioneer a new field to help prevent poaching and possible future extinctions – and it’s called astroecology. In the Daphne Oram Award Lecture at this year’s British Science Festival, Claire will introduce and illustrate her work.


In today’s social and political climate, the idea of ‘fake news’ is on everybody’s mind - the idea that the lines between truth and lies are being blurred by higher powers. But how do we define a lie - or the truth? In this session, Jennifer Parrott will seek some answers.

Your blurb might challenge received wisdom.

Being fat is unhealthy, yes? Well, not quite. And it certainly isn’t an ‘epidemic’. Dr Oli Williams believes that we need to rethink our approach to weight. In the Margaret Mead Award Lecture for social sciences at this year’s British Science Festival, Oli will challenge some of our most fundamental assumptions about obesity.

If you want to go further, this post looks at messages in more detail; this one and this one explore how to structure the presentation; and this one lists seven ways in which you can bring your ideas to life.

I work with presenters at the British Science Festival each year, helping them to develop their ideas and design their presentations. If you'd like to do the same, contact me by posting a comment on this site, finding me on LinkedIn or sending me an email.


Communicating science: a selection of blog posts from the British Science Association



I've been blogging for the British Science Association for about three years. Here is a selection of my posts. Please browse.


The AI Revolution: Jim Al-Khalili’s Presidential Address 2018

Don't take my word for it: Dame Uta Frith's Presidential Address 2017

What are universities for? Dame Nancy Rothwell's Presidential Address 2016

In the driving seat: what’s the risk with epilepsy?

Resilient reefs BSAblog

A future divided?

The weight of expectation

Shedding light on baby brain injury

Hunting for a Huntington’s treatment

Getting in the neural groove

From kings to keyholes

Will you be my friend?

The acoustics of nature

Can astronomy save Earth’s species?

OCD: living with a monster

Can music change our immune system?

Reaching for the stars with George Abbey

The calculus of contagion

I work with the Award Lecturers at the British Science Festival each year, helping them hone their presentations and develop their skills. If you're interested in working on similar scicomm presentations or projects, I'd love to hear from you.

Then again, you might be interested in hiring me to write a blog post. I'd love to.

Email me:

[email protected]

Cochlea of the inner ear, Dr David Furness Wellcome Images, 2011