Explanations are absolutely vital in teaching yet they are largely ignored when we plan and prepare lessons. This is an oversight that should be put right.
We need to pitch explanations expertly: not too easy, not too hard, but just right. Let's call it the Goldilocks principle. The good news is that there is plenty of research out there to help.
Assess prior knowledge
A crucial starting point is to ask a lot of questions in order to ascertain students' prior knowledge. As Slava Kalyuga and colleagues state in their 2003 paper "The expertise reversal effect", if students know a lot already, then too much repetition will clog up their working memory and stifle their capacity to learn anything new (bit.lyExpertiseReversal).
But how effective are we at discovering what our students know? Not very. It's clear from Arthur Graesser and Natalie Person's seminal 1994 research that our questioning has room for improvement (bit.lyQuestionAsking).
While students seldom initiate their own questions (a very good indicator of their understanding), the queries we put to them are too often closed and simple. We need to ask deeper, open questions that really probe their understanding of the explanation we have given.
Simply asking "When did Martin Luther King die?" in a history class has some value, but asking "Why was Martin Luther King's death a turning point in American history and politics?" is more likely to challenge students, forcing them to elaborate and retain knowledge in their long-term memory.
Balance real and abstract
Once we have ascertained prior knowledge, we need to achieve a delicate balance between using real-life examples in our explanations and teaching more abstract ideas and concepts.
The need for a concrete understanding never leaves us. Take teaching parabolas in mathematics. Real-life examples, such as throwing a basketball or launching a catapult, are eminently useful. But, crucially, they are not enough.
In the 2008 paper "The advantage of abstract examples in learning math", Jennifer Kaminski et al show that although real-world examples are a good starting point, students won't reach a thorough understanding of how to calculate a parabola unless the explanation moves quickly on to abstract equations (bit.lyAbstractExamples).
Keep it simple
We should also be wary of technological bells and whistles or attempts to "keep it real". A great explanation doesn't need glossy animations or YouTube videos to be memorable. In fact, 2005 research by Richard Mayer and colleagues shows that using still images can prove more effective than using animations. The reason is probably that students are forced to think about the image actively, whereas a clip can overstretch their memory capacity (bit.lyStaticMedia).
Know thy student
A great explanation does require interesting examples to vie for attention in the minds of our students. We also need to model successful outcomes. And then, like teaching someone to ride a bike, we need to take the training wheels off, reducing modelling and example-giving so that pupils can work with greater independence. The process is subtle and requires in-depth knowledge of the young people in our class and their understanding at every step.
So next time you're planning, don't just concentrate on content; take time to formulate your explanations, too.
Alex Quigley is director of learning and research at Huntington School in York. He tweets at @HuntingEnglish and blogs at www.huntingenglish.com and his latest book The Confident Teacher will be out later this year
After giving students an explanation, get them to condense your core message into three simple images and explain their meaning.
This activity encourages students to create mental structures (psychologists would label them schemas - helpful frameworks for organising knowledge). It is great for ensuring that they are thinking hard about the content and distilling the most important information.
This simple activity will encourage students to think hard about the explanation they've just heard.
First, challenge them to represent your core message in just 10 words. This is generally doable with some crafty editing. Second, ask students to cut the explanation down to three key words. Finally - you guessed it - they need to summarise the whole explanation in a single word.
Although a little reductive, this is a fun way of thinking and talking about the core message of an explanation.
A Teachers TV video on how to go from good to outstanding.
PowerPoints to encourage effective communication.