Spaced Practice

What spaced practice is

Spaced practice, also called distributed practice, is the delivery of training in short sessions separated by intervals of time, as opposed to gathering it into one continuous session. The total time can be the same in both cases; what differs is how that time is distributed.

Spaced practice is a decision about the design of a programme, not about its content. The same material is taught under either schedule, but what changes is when it is taught and how many times the trainee is asked to return to it.

The opposite of spaced practice is massed practice, which delivers the whole programme in a single continuous block with no planned interval. Massed practice is defined by having no interval and spaced practice by the interval, and the interval that counts is one in which the trainee returns to work and then comes back. Whether a programme is delivered in a single block or over spaced intervals is one of the things the design stage of the ADDIE model has to settle.

Why spaced practice divides sessions instead of gathering them

A single long training day is convenient for whoever organises it: one booking, one journey, one absence from work. Its price appears after the day, not during it.

• Attention can decline within a long session, so the last two hours can reach people who are present in body only.
• What is not retrieved can be forgotten by the person who learnt it. The interval is what makes retrieval necessary, because the next session opens by asking the trainee to return to what came before.
• The difficulty the interval creates is intended. The reasoning is that retrieving what has faded holds better than rereading what has not yet gone, and that the ease of recall inside a single session can give a false impression of mastery.
• The interval allows application. The trainee goes back to work, meets a situation that concerns what was learnt, and brings back the question that would not have occurred to them in the training room.

Those are the reasons given for spaced practice, and they describe a mechanism, not a measured result. In the sources we reviewed, we found no published measurement on which to base a claim about whether spaced practice or massed practice has the more lasting effect, or by how much.

The interval as part of the design of spaced practice

In spaced practice the interval is not a gap to be tolerated but a period whose contents are planned. At a minimum, three things are placed in it: a small task carried out in the work itself, a short question through which the previous session is retrieved, and a known date for the next session.

The length of the interval follows from how the skill is used. A skill used every day needs only short intervals, and a skill used on separate occasions needs retrieval at separated points that resemble its use.

What holds for the interval also holds for the order of topics. Taking two or three topics in alternation across the programme is more useful than finishing the first before starting the second, because alternation requires the trainee to tell which rule applies to which case, and that is what the job will ask of them.

Spaced practice in figures: one total, two schedules

Take a programme with a total of 12 hours delivered in two ways. The first is two consecutive days of 6 hours each, so 2 multiplied by 6 gives 12. The second is 6 sessions of two hours over 6 weeks, so 6 multiplied by 2 also gives 12. In both cases the hours are equal, but what differs is the number of points that have to be managed.

• In the first schedule there are two appointments to book, absence from work in two continuous stretches, and no interval to fill.
• In the second schedule there are 6 appointments and 5 intervals between them, and each interval carries a task and a retrieval question. The total is 6 plus 5 plus 5, which gives 16 points to plan and follow up, against 2.

That number is the real cost of spaced practice, and it is why spacing can fail in organisations that adopt it without assigning someone to follow it through. The decision is not between two designs on paper but between 2 points of follow up and 16.

Against this, the first schedule carries a number that does not appear in the timetable: any occasions on which training has to be repeated months later for people who did not retain it. Those occasions are not counted against the programme, because they are recorded under another budget line in another year.

The session counts above are an example of how the calculation works, not a recommendation of an optimal number of sessions for a given total of hours.

How the interval in spaced practice is set

An interval chosen without a rule can end up suiting the training room rather than the skill. The working rule is that the interval should resemble how frequently the skill is used. A task performed at work every day can be served by an interval of about a week, and a task performed once a month needs an interval of about a month, because the trainee will retrieve it at work at that same spacing.

An interval longer than the gap between uses delays application until forgetting has come first. An interval shorter than that gap gathers the sessions into a period in which no use takes place at all, so the trainee brings back no question from work, having met no situation there yet.

This rule is derived from the nature of the work, not from a published source. In the sources we reviewed, we found no published interval length, in days or in weeks, on which to base it.

Training that does not suit spaced practice

• What must be mastered before starting work. Training that is a condition for beginning the job is not split so that half of it waits until next month.
• A skill that cannot be divided. Splitting it into two halves means the trainee performs an incomplete half twice.
• Training that needs costly preparation for every session, such as stopping a piece of equipment or gathering a dispersed team. Here the interval has a price that is weighed against its benefit.

The effect of spaced practice on the training schedule

A spaced programme is heavier for whoever runs it: more appointments, more attendance tracking, and reminders between sessions. That cost is administrative and visible, and it is set against a cost in the massed programme that is not visible, namely any retraining that may be needed months later.

The implementation stage of the ADDIE model includes whether participation is recorded in a learning management system, and under spaced practice that record has a practical use. A system that records who completed which content and when shows who has dropped out after missing a session, before the programme moves on without them.

What comes before the decision to use spaced practice

Spacing the sessions is aimed at what remains from training, but it does nothing for the choice of what is trained. Training needs analysis asks first about the gap between the performance required and the performance found, and whether training is what closes it; in the ADDIE model that analysis is the first stage, and its output states which gap, for whom, and by which indicator its closing will be recognised. A programme that addresses no existing gap has no effect, whether it is spaced or massed.

The training best suited to spaced practice is training that extends a path the employee is already on. That is the territory of upskilling, in the sense of developing an employee within their current path without moving them to another specialism.

What resembles spaced practice but is not

• A single day cut into two consecutive days. The interval here is one night, and neither use nor retrieval happens in it. The organisation has carried the burden of two appointments without gaining what spacing is meant to provide.
• Presenting the same content again in each session. Repetition is not retrieval: in the first the trainee reads what is in front of them, and in the second they are asked to produce what they hold before it is shown to them. That difference is where the benefit lies.
• Postponing half of the material for lack of time. It is a forced delay, not a design, and the sign is that nothing was planned for the interval, so the second part opens by repeating the first.

What the three share is a timetable that looks spaced while the programme is not. A single question tells them apart from spaced practice: what was the trainee asked to do during the interval? If there is no answer, there was no interval, only a break.

When the effect of spaced practice is measured

Measuring the effect at the last session captures the moment closest to the presentation and furthest from the question the programme was built on, which is what remains after time has passed. Measurement under spaced practice is therefore built on three points, not one:

• At the start of each session, through a short retrieval question about the previous one. It serves two purposes: it tells the trainer where the trainees stand, and at the same time it performs the retrieval for which the interval was created.
• During the interval, through the task carried out in the work itself. What is observed there is closer to real conditions than what is observed in the room.
• Some time after the programme ends, at a distance close to how frequently the skill is used. This is the measurement against which the design is judged.

Leaving measurement to the third point alone delays the discovery of a fault until it can no longer be corrected within the programme, and relying on the first two alone produces reassuring figures about a period that has not yet been tested.

Settings where spaced practice is harder to arrange

• Shift work. The same team may not come together at a fixed time each week, whether shifts are assigned by a supervisor or allocated through shift bidding. One solution is to repeat each session for another shift, and its price is doubling the number of appointments counted above.
• Seasonal teams. A peak period falls inside the programme and one or two sessions are cancelled. The decision here belongs before the start: either the programme is scheduled outside the peak, or it is limited to content that can tolerate an interruption.
• Several sites. What happens in the intervals differs from one site to another, so the next session opens with two different levels in the same room.
• Very small teams. A single absence is enough to empty a session of its purpose, and the interval becomes waiting rather than retrieval.

What undermines spaced practice

• Intervals with nothing in them. They turn into scheduled forgetting, and each session then opens by repeating the one before.
• Sessions placed so close together that they become one divided day. The reason for spacing disappears and its burden remains.
• Attendance that differs between sessions. The third session then builds on what half of those present did not attend.
• Leaving the manager out of the arrangement. A manager who does not know that an employee has a task between two sessions does not free the employee for it.
• Measuring the effect at the last session, the worst time to measure a programme built entirely on what remains after time has passed.

In the sources we reviewed, we found no provision addressing the spacing of training sessions as such, so we state neither that spacing is required nor that it is prohibited.

This is an explanation of the concept, not legal advice.

Related terms

• Massed Practice
• ADDIE Model
• Rotational Training
• Work Sample Test
• Performance Standards