For help on using Computing content on Eedi click here.

Computing at School (CAS) and Eedi, in partnership with others (including OCR, Edexcel, Microsoft, Google, ARM), have developed a bank of diagnostic questions to support the computing curriculum across Key Stages 3 to 4, that will:

  • Improve the quality of teaching and learning in computing

  • Save you time and reduce your workload

The entire collection covering both KS3 and KS4 is available to schools and students, for free, forever. You’ll find everything you need to know about Eedi, Diagnostic Questions and the Computing quizzes and questions in this guide!

What content we have on Diagnostic Questions

The Diagnostic Questions platform has over 11,500 questions on the Computing curriculum available, here. Many of these questions were written by CAS members; others were donated by a variety of partners.

In addition, we have curated several large sets of quizzes (a “quiz” is just a collection of 10-20 questions), to save you the work of choosing questions:

5 steps to get started

  1. Login to your account on Diagnostic Questions

  2. Add your students via a spreadsheet (during Covid we recommend infilling email and choosing a password in the spreadsheet to make it as easy as possible for students to login)

  3. Choose content (see above) and assign a quiz

  4. View your results. If you want to download your quiz results, you can do this on Eedi. See how-to here.

  5. Give feedback to your students

If you need any help, drop us an email -

The research behind diagnostic questions

The focus of the Computing collection on DQ is squarely on formative assessment: using low-stakes quizzes to improve the quality of teaching and learning:

  • Use diagnostic questions in class, as a pedagogical tool

  • Use a diagnostic quiz, which the students can do overnight on their phone, to give insight into what the students have learned, and what misconceptions they hold

  • Data from a series of quizzes give both students and teachers insight into their progress, and areas that need more work.

With such individualised information, students achieve a deeper understanding of their own strengths and weaknesses and feel more confident in their learning.

All the questions in DQ are multiple-choice questions (MCQ). Many people think that MCQs are second-best, useful only because they are easily marked. But the research says the opposite: in fact, high-quality MCQs are extremely effective at promoting learning.

The “high quality” bit is important! As part of our partnership, Eedi and Microsoft Research are also developing ways of learning, from anonymised data on hundreds of millions of answers to tens of thousands of questions, which questions “work well”, how hard they are, and which is most suitable for a particular student or class. Here’s an early video about this work.

For more information see:

Let's look at a diagnostic question.

We're going to look at an innocent-looking question about the bubble sort algorithm. What could possibly go wrong?

What do you think the most popular wrong answer is, and why might a student select it?

And here are the results (with almost 5000 people attempting this question!)

So, less than 30% of students get this question correct.

Okay, so why do students get this question wrong? Well, let’s dive into some student explanations to try to find out.

For each incorrect answer, the author writes an explanation so we can compare these with the explanations students give.

Answer A

Author explanation: The students think it is one pass per number of items

Student explanation: "because thats how many numbers there are"

Answer B

Author explanation: The student assumes the algorithm knows the list is sorted

Student explanation: "the list is already in order, there is no need to sort the list, its already in ascending order from low to high."

Answer D

Author explanation: The student thinks it is the number of items - 1

Student explanation: "because after three numbers have been checked youd know for sure that it is in the correct order"

Let's not forget the correct answer and the real student explanation for the correct answer:

Answer D from a student: "Because its already sorted so it just needs to check that the order is correct which it is"

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