Learning and development (L&D) professionals have been struggling to make learning stick for decades. The forgetting curve, theorized in 1885 by Hermann Ebbinghaus, posits that learners forget new information exponentially after learning it. The eternal thorn in the side of learning and development, retention is a crucial consideration when developing training content. And with training expenditures steadily increasing (in 2019, companies worldwide invested $370.3 billion in learning and development), it’s even more important to increase the return on investment (ROI) on training programs by finding ways to improve learning retention.

But what does it look like to successfully combat the brain’s natural tendency to forget? Web-based training and on-the-go microlearning are great options for sustainment, but it’s not enough for them to simply reteach the same information. The most effective way to retain information over the long term, according to recent neuroscience research, is through “effortful recall.”

Based on Dr. Henry Roediger’s research in memory and learning retention (see his book “Make It Stick: The Science of Successful Learning,” and recently popularized by Dr. Art Kohn, effortful recall — in the form of retention “boosters” sent to learners after training — is the best way to counter the forgetting curve. Every time learners have the opportunity to recall what they’ve learned, the booster effectively tells their brain, “This information is worth retaining,” dramatically improving the long-term retention of your training material.

L&D experts have made many recommendations for how best to deliver retention boosters over the years. However, whether due to client preferences, organizational red tape or an unwieldy learning management system (LMS), it’s not always possible or practical to implement the ideal post-training retention strategy.

When it comes to improving knowledge retention, providing learners with any opportunity to effortfully recall what they’ve learned is invariably better than providing nothing at all. You can still offer retention opportunities that are engaging, measurable and cost-effective, even in less-than-perfect circumstances. Here are five practical ways to deliver retention boosters:

1. Develop Questions That Challenge Participants

Simple questions will not boost retention. Your questions must be difficult enough that participants are required to actively recall information. Whether they answer correctly makes little difference — it’s the act of effortful recall, coupled with immediate corrective feedback, that helps participants retain the information over the long term.

Always start with your training objectives when writing booster questions. What information do you want participants to walk away with? Your boosters don’t have to touch on every topic covered during training. Though the topics that you do cover will show the greatest retention, boosting just one piece of information can improve retention for the entire learning experience.

2. Meet Participants Where They Are

On-the-go mobile learning is not the exception anymore. We still tend to rely on email messaging when it comes to delivery, however, even as rates of engagement continue to dwindle. Sending retention boosters via a text message, when possible, is a unique and cost-effective solution that can engage participants more effectively. Text messages boast open and response rates as high as 98% and 45%, respectively, compared to just 20% and 6% for email. And with a variety of affordable text platforms, it’s easier to send multiple boosters to large groups of participants after training. Just make sure you’re following all relevant data privacy laws.

An important part of a successful retention booster is immediate corrective feedback when the learner answers incorrectly. When selecting a text platform, make sure that you can program specific corrective feedback responses to learner answers.

3. Boost the Boosters to Encourage Participation

Set up your post-training retention strategy for success by ensuring that you include key booster information (such as what they are and when learners should expect to receive them) in your pre- and post-training communications. For instructor-led programs, have your facilitator build learner interest and buy-in by explaining what the retention boosters are, when learners will receive each booster and how they will help them successfully retain the information they learned during training.

4. Deliver Boosters in a Timely Manner

When it comes to retention boosters, time is of the essence. Kohn recommends sending your boosters in three phases, following “2+2+2” timing: two days after training, two weeks after training and two months after training. If you are unable to send your boosters in this specific timeframe, a general rule of thumb is to send your first phase of boosters within two weeks of training’s completion.

5. Tie Boosters to Actionable Analytics

Tracking learner retention data can be difficult, especially if you can’t gather detailed analytics. If your booster delivery method doesn’t track specific learner data, you can still measure engagement through completion analytics. Track how many of your learners have completed each booster, or which boosters have been completed the most and the least, to gain valuable insights into any changes you should make to your boosters or communication strategy. If you can track individual performance, ask your learners how they’ve used their training since the event — and identify any behavior differences between the learners who completed the boosters and the ones who didn’t.

You can also track booster performance and learner retention by offering two identical post-tests: one immediately after learners complete training and one after they complete all retention boosters. If retention doesn’t decrease between the first and second post-test, your boosters were effective.

In an article for Learning Solutions called “Brain Science: Overcoming the Forgetting Curve,” Dr. Kohn implores: “If your goal is to produce long-term retention … then what you do after training is more important than what you do during training.” You can’t ignore the importance of including a post-training retention strategy in your curriculum — but it doesn’t have to be perfect.

Don’t let your training go to waste because your learning environment isn’t ideal. Find ways to provide learners with opportunities to effortfully recall and boost their learning, and you will drastically improve both training ROI and learning retention over time.