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Why is good assessment critical and what makes it effective?

In some form or another, assessment is being carried out by the teacher almost every minute of the lesson. Assessment is an integral part of the teaching and learning process. Effective assessment is critical to teaching because it provides teachers with information about pupils’ understanding and learning needs.

The function of assessment sounds relatively simple: find out what the pupil knows, and doesn’t know, and plan subsequent opportunities to impart the relevant knowledge or skills based on the identified need. And yet, it can be a challenge to reliably assess a pupil’s level of understanding. For example, an ‘on-task’ child may appear to understand their learning, yet the work they are so busily producing may be full of errors based on an unidentified misconception. In the same way, only by removing the learning scaffold from a seemingly confident pupil might you discover that they cannot replicate the learning in a standardised test – implying that the knowledge was not firmly encoded into the long-term memory in the first place. It is therefore critical that you have a clear understanding of what makes assessment effective in order to best support impactful teaching and learning decisions.

Good assessment provides teachers with reliable information about pupils’ understanding. However, for this information to be of real value, the teacher must use it effectively to inform feedback and support pupils to move forward.

Watch Professor Rob Coe as he explains why assessment is such a powerful teaching and learning tool, and what information it can give you about your pupils. You can make notes in your notebook if you wish.

Video transcript

Dylan William defines assessment as the bridge between teaching and learning. The key insight is this: just because you’ve taught it, don’t assume they’ve learnt it. In general, complex processes like teaching and learning need feedback to ensure that they’re on track. Assessment gives feedback about two kinds of things. Firstly, whether specific ideas have been understood, knowledge has been absorbed, integrated, connected, retained, and procedures can be performed fluently. This is often quite granular and specific. Second, the overall status and progress. Am I on track? What is the gap between actual and desired performance?

Feedback is a key element of assessment and feedback can act in a number of ways. The simplest may just be correction – points out things that were wrong that could easily be corrected. Slightly more complex is guidance – we give students advice or activities that are tailored to their needs. Sometimes though, even that is not enough. A common mistake is to try and give feedback when what is really needed is instruction. If a student has not understood a key idea, then just feedback may not be enough.

Most learning and thinking is not directly visible so assessment is our only window. We ask questions to find out what is in learners’ heads. It’s useful to think about this in terms of information. Each individual question provides limited information, so we need to ask lots. Good assessment gives us information that is accurate and trustworthy. Teachers need to understand in principle what makes assessments accurate and trustworthy and, specifically for any given assessment that they want to use, how good it is.

Classroom assessment is powerful if it helps to inform and improve decisions and actions. This is always a matter of professional judgement – the teacher has to decide. But information from assessments can help to make it a better-informed decision. For example, the kinds of decisions teachers might make include:

  • Does this individual student need specific support or help?
  • Does a group need additional help or input?
  • If I teach this again, could I do it better? It’s important to understand that assessment can serve a number of different purposes. Designing good assessments and judging whether an assessment is high-quality crucially depends on knowing the purpose.

As highlighted by Rob Coe, good assessment gives teachers a window into their pupils’ minds. The questions that are asked and the tasks that are set provide insight into the information that has been processed and subsequently stored in the long-term memory. Throughout the video he also emphasises the importance of the two-way nature of feedback. For the teacher, good assessment makes clear the knowledge that has been understood. It also gives the teacher information as to whether they need to reteach concepts or work further with a small group. For the pupil, feedback provides a way to move forward with their learning and helps them to develop secure mental models around a concept.

In order to ensure that the information you gather is accurate, Rob stresses that it is crucial to know the purpose of the assessment. The next section will explore how you might decide on the purpose of your assessments.

What makes assessment effective?

Deciding on the purpose of the assessment

You will most likely have come across the terms ‘formative’ and ‘summative’ assessment during your initial teacher training.

The concept of formative assessment was made popular by Dylan Wiliam and Paul Black, who defined formative assessment as when teachers ‘use evidence of student learning to adapt teaching and learning, and instruction, to meet a student’s needs’ (Inside the Black Box, 1998). As such, it is generally used to inform future learning or teaching. In some instances, formative feedback can be immediate, and pupils are able to act on it instantly.

‘Summative’ assessment is a term usually used to describe assessment carried out at the end of a period of learning, as a way of ‘summing-up’ what a pupil knows. Results of a summative assessment may often be shared as a grade or level description (e.g. Emerging), and generally offer a shared meaning on pupil performance.

Video transcript

So very crudely formative assessment is generally understood as using assessment to inform future learning or teaching and I tend to stress both learning and teaching. It usually means the use of assessment to check learning has taken place. And is it the learning that we intended, and if not what are we going to do directly about this. In short, it has to influence further development. It could involve the learner alone, identifying an error or gap in their knowledge by checking his or her own work, or against an exemplar, or in a conversation with a peer, but this really does need structure. Or it might be the teacher asking probing questions to check that learning has taken place and used to identify gaps or misconceptions. But either way the action requires a further action.

Summative assessment conversely is usually a term used to describe an assessment at the end of a period of learning. For example, at the end of a topic, at the end of the year or the end of a course, to show what has been achieved or not. These outcomes often use information such as marks, grades, pass/fail, merits/distinction. But no other detail is given back to the end-user. But although it’s worth trying to understand what people actually mean when they use such terms, I wouldn’t get too attached to either of these terms as types of assessment because they’re not types. In reality these terms describe in quite blunt terms and very broad terms a purpose to which we put a particular assessment.

Paul Newton listed I think about twenty-two purposes for assessment, so the starting point has to be around the purpose. As for educational assessment, be it about questioning, about teaching session, designing the written examination or test, the key questions are, ‘What really are we trying to assess? Why are we trying to assess it and what are we going to do with the outcomes? How are we going to record or share the outcomes with other people?’ Then you can ask about the best way that this can be achieved.

Allocating labels like formative, often referred to Assessment for Learning, and summative, often referred to as Assessment of Learning, is quite a blunt approach and can actually be misleading. For example, in so-called summative assessment, for example, a GCSE or a Key Stage Two test, even here there are formative possibilities. Both of these assessments result in production of analysis. Item analysis where you can get a look at the performance of individual questions, so for example you could analyse the outcome of the questions to see how your school or pupils did on question one compared to question three. And that might be something about how we taught the topic or even did we even teach that topic? The outcome of this investigation may not be formative for the pupils, they’ve now left the school. But the analysis might help the teacher to identify areas of weakness in the teacher’s knowledge gaps or course coverage. That could be considered as formative in a sense, at least in my view, because that would inform future teaching and probably some professional development for the teacher.

So for me these terms describe the use to which a particular assessment is put rather than being a type of assessment, in that the same test instrument could be used for either purpose in effect. A particular concern, at least to me, is that these terms are too often presented as being polarised as though if they were at some different ends of a spectrum and in opposition. But in reality they’re not; you could use one test, one question, and put the outcome to different purposes. So they’re not types of assessment but dependent on the inferences that we take, the conclusions that we reach or we draw on the evidence that we’ve elicited from our assessment. So be wary of labels and focus on what it is that you want to assess and what you want to get out of an assessment.

As highlighted by Mick, effective assessment has a purpose, and before using any assessment, teachers should be clear about the decision that the results will be used to support, and able to justify its use. When deciding on which assessment to use, consider the following questions to help you select which method is going to be most effective:

  • what are you trying to assess?
  • why are you trying to assess this?
  • what are you going to do with the information?
  • how are you going to feed back the information to pupils?

Although it is certainly important to be aware of the terminology surrounding assessment, when considering what is effective in assessment, Mike highlights the possibility of using summative assessments in a formative way (for example, working on a single exam question during a lesson), or using information you have gathered in your formative assessment in your summative judgments. He instead asks teachers to focus on the purpose for the assessment, and to be clear on the decision it will be used to support.


A teacher has reflected on the purpose of an assessment opportunity they have planned for their next lesson.

They answered the four questions in the following way:

What are you trying to assess?

I want to assess whether my pupils have grasped the concept of a coordinating conjunction.

Why are you trying to assess this?

I am assessing their knowledge of this for two reasons:

  1. To determine which, if any, of my pupils are ready for independent practice.
  2. To help me decide where to direct my attention in the next part of the lesson.

What are you going to do with the information?

The assessment information will tell me whether I can move onto the next part of the lesson, which will focus on pupils’ independent practice of the knowledge.

How are you going to feed back the information to pupils?

The feedback to pupils is going to be almost immediate, as I will give them the answers to the multiple-choice questions. Based on their score, I will direct them towards the next task in the lesson. This may be independent practice, or a reteach by me.

This progression is usually a thought process undertaken when planning and is not typically written down. However, this is a good opportunity to take a few minutes to capture your thoughts and be able to discuss them with your mentor.

Select an upcoming assessment opportunity you have planned. This could be from a lesson or the assessment of a unit of work. Consider the purpose of the assessment and answer the questions below:

  • what are you trying to assess?
  • why are you trying to assess this?
  • what are you going to do with the information?
  • how are you going to feedback the information to pupils?

Be prepared to discuss this activity at your next mentor interaction.

Assessment tasks linked to the lesson objective

Let’s return to the questions posed by Mick Walker when deciding on the purpose of assessment:

  • What are you trying to assess?
  • Why are you trying to assess this?
  • What are you going to do with the information?
  • How are you going to feed back the information to pupils?

Once these questions have been considered, the only question remaining is ‘how are you going to assess learning?’

There are multiple ways you could assess pupil understanding. The ‘how’ might take the form of questioning, a matching activity, a low-stakes quiz, a performance, through interacting with play, or various other methods that might lead to an indication of pupil understanding and highlight gaps in knowledge. The key is to make sure that the ‘how’, in whatever form that takes, is linked to the lesson objective and always supports you to indicate levels of understanding.

Read the recount below from teacher and NQT mentor Mathew Sullivan. Mathew explains how the teacher had planned for the class to write a newspaper report as the assessment task, but that it didn’t create the assessment opportunity the teacher had hoped for.

Recount by Mathew Sullivan

I observed a KS2 lesson on the Viking invasion at Lindisfarne. The lesson objective was very precise and would have allowed the teacher to make clear inferences about levels of pupil understanding. The objective was to recall the date and key events of the attack on the Lindisfarne monastery. Before the lesson we had spoken as a phase team about the five key pieces of knowledge we wanted pupils to recall from the invasion, and together we had created a presentation that emphasised these. The beginning of the lesson was very effective, and the teacher even asked members of the class to act out key moments, which really brought the learning to life. The teacher then set the pupils a task to write a newspaper report on the events of the invasion as a method of assessing whether they could recall the key historical facts. When we sat down after the lesson and looked at what the pupils had learned, the results were somewhat below par. For the majority of the class, the format of the newspaper article had added a layer of complexity to the task that had distracted them from fully achieving the learning objective. Some had written very little, others had not written in the style of a newspaper article and had instead written prose as if they were answering a question, and only a small number had managed to achieve the correct newspaper features, but even they had difficulty ordering the events and deciding whether they should be writing from the perspective of an eye-witness, or the reporter themselves. When reflecting on why they had selected the newspaper report as an assessment task, the teacher explained that they thought it would be a ‘fun activity’ for the class to complete. However, with it being a full term since the class had completed a unit on newspapers, and no retrieval of key features had taken place in the lesson, the pupils were not able to demonstrate their learning effectively; remembering how to write a newspaper took precedence over recalling the key historical events. It has been my experience that my mentees can be more concerned with the ‘activity’ for the lesson, often asking themselves ‘what are we going to do tomorrow?’. The question that I often tell them to ask themselves instead is ‘what are we going to learn tomorrow?’. It is a subtle distinction, but one that puts the focus squarely onto the learning. As the objective of the lesson had not being around creating a newspaper article, we discussed different activities that they could have set in order to meet the lesson objective. My mentee decided that a simple recount would have allowed pupils to better demonstrate their learning, and in turn would have provided a clearer indication of their understanding. We did both agree that a newspaper report would be an engaging way to recall the tale of the invasion, but only once the foundational knowledge of the events was assessed as secure, and the features of a newspaper article had been recalled.

This case study highlights the need to carefully consider the assessment tasks you plan for your class. Is the task giving pupils the opportunity to demonstrate their learning towards the lesson objective, and will it give you information about misconceptions or gaps in their knowledge?

Good assessment helps teachers avoid being overly influenced by potentially misleading factors. In this instance, the teacher could have made some inaccurate inferences on pupil learning because the assessment task they set was not an effective method of assessing the target learning. If the task had been to write a recount of the events, the class would most likely have achieved a higher success rate, and the subsequent assessments would have been more accurate.


Select a lesson that you will be teaching this week. How aligned are the lesson objective and assessment task that you have planned?

Consider these questions:

  • is the lesson objective achievable and measurable?
  • does the assessment task allow the pupils to demonstrate their learning?
  • how will the completion of the task support you to identify levels of pupil understanding?