Tes Maths: Pedagogy place - Spacing

What is the spacing effect, and how can you best harness it in your lesson and homework activities? Tes Maths finds out

Craig Barton

Tes Maths: Pedagogy Place - Spacing

In this series, we dive into the realm of educational research to help you best formulate effective classroom practice

What is the spacing effect and how can we ensure that our students reap the benefits of it in our lessons and homework activities? Let’s find out.

What does the research say?

While previously we’ve researched how teachers can avoid imposing an unnecessary burden on the working memories of students, Bjork and Bjork (2011) also discuss the concept of desirable difficulties.  In short, these are techniques that increase retention and transfer of knowledge through making the retrieval practice harder in the short term.

One example of a desirable difficulty is the spacing effect. This refers to the finding that the learning of new information is strengthened when material is studied over a period of time, rather than in one single session.  As Willingham (2012) explains, “distributing study time over several sessions generally leads to better memory of the information than conducting a single study session”.

In fact, the spacing effect has been shown to be very powerful indeed. For example, in their meta-analysis of spacing studies, Donovan and Radosevich (1999) discovered that the average learner receiving distributed training retains more information than approximately 67 per cent of those receiving massed training.

So, how can teachers take advantage of the spacing effect in the classroom? According to Carpenter et al (2012), there are three ways:

  1. Through dedicating part of each lesson to reviewing concepts learned several weeks earlier, either in a starting activity or with a low-stakes quiz
  2. Through re-exposing students to previously learnt information with homework assignments
  3. Through giving cumulative exams and quizzes, covering both current and previous topics

This then begs the question of what the optimum length of intervals between practice sessions should be, in order to ensure that pupils are able to take full advantage of the spacing effect.   

Unfortunately, there is no easy answer. Cepeda et al’s (2008) statistical model suggests that for a test within 60 days, the optimum gap before restudy may be ten days. However, in reality, the length of intervals between study is entirely dependent on a number of different factors, including the complexity of the material, the ability and prior knowledge of the students, and how often a topic can feasibly be revisited before assessment.

In summary

The spacing effect is a powerful phenomenon, and one that we can harness relatively easily. Through regularly revisiting previously covered material, students’ learning, retention and retrieval can be greatly increased. However, in order to ensure that our pupils fully reap the benefits, the careful planning of lessons, homework materials and in-class quizzes is required.

How can Tes help?

Lesson starters, question generators, homework quizzes… There are plenty of engaging ways to revisit key topics. Ensure that your students benefit fully from the spacing effect and retain crucial maths knowledge with the help of these stimulating activities.  

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Craig Barton, TES Maths adviser

Craig is a secondary maths teacher in the North of England.


  • Barton, Craig. Mr Barton Maths Podcast - Robert and Elizabeth Bjork. (2017)
  • Bjork, Elizabeth L., and Robert A. Bjork. "Making things hard on yourself, but in a good way: Creating desirable difficulties to enhance learning." Psychology and the real world: Essays illustrating fundamental contributions to society 2 (2011): 59-68
  • Cepeda, Nicholas J., et al. "Spacing effects in learning: A temporal ridgeline of optimal retention." Psychological science 19.11 (2008): 1095-1102
  • Carpenter, Shana K., et al. "Using spacing to enhance diverse forms of learning: Review of recent research and implications for instruction." Educational Psychology Review 24.3 (2012): 369-378
  • Donovan, John J., and David J. Radosevich. "A meta-analytic review of the distribution of practice effect: Now you see it, now you don't." (1999): 795
  • Willingham, Daniel T. "Ask the Cognitive Scientist Allocating Student Study Time" Massed" versus" Distributed" Practice." American Educator 26.2 (2002): 37-39