1. What the Research Shows: Email Reminders Can Increase Saving
A large new study led by researchers including Katy Milkman (Wharton) analyzed data from nearly 2 million bank customers to test whether reminder emails would encourage them to transfer money into savings accounts. (Phys.org)
- Reminder emails work as “nudges” — they help people remember to take an action they intend to do but often forget, like moving money from checking to savings. (Phys.org)
- Overall, customers who received emails were slightly more likely to make a one-time savings deposit in a given month (an increase of about 0.05 percentage points, or roughly 0.5%). (Kellogg Insight)
2. Frequency & Type of Email Matter
Not all reminders are equally effective:
- Weekly tailored reminders — which either prompted a transfer for customers who hadn’t saved or congratulated those who already had — were the most effective. (Phys.org)
- These weekly messages boosted the likelihood of a savings deposit by about 1.3% compared with no emails, the strongest effect seen in the study. (Knowledge at Wharton)
This suggests that frequent, personalized communications catch attention better and encourage action more than generic or less frequent messages. (Kellogg Insight)
3. Why Reminders Help People Save
They Increase Awareness
Many people intend to save but simply forget — regular reminders bring savings goals to the front of customers’ minds. (Phys.org)
They Reduce “Friction”
When an email includes a specific call to action (like clicking to transfer funds), it reduces barriers between thinking about saving and doing it. (Kellogg Insight)
They Reinforce Good Behavior
Congratulatory messaging for customers already saving can reinforce positive habits, tapping into behavioral psychology principles. (Phys.org)
4. Impact at Scale
- Although the effect per individual is modest, the impact is cost-effective for banks: sending reminder emails costs almost nothing, yet scaled to millions of customers it could lead to millions of extra dollars saved collectively. (Kellogg Insight)
- The researchers estimated that if the best email campaign were sent to all participants over the two-month period, it might have boosted total savings by around $6 million to $10 million. (Money)
5. Limits & Considerations
Small Individual Effect
The average increase in savings was small for individuals, and email is easy to ignore, especially compared with more proactive interventions like automatic transfers. (Phys.org) User Experience Matters
The impact may be limited if customers can’t easily complete savings actions (e.g., set up automatic transfers in the bank’s app). (Knowledge at Wharton)
Broader Evidence: Reminders Work Beyond Email
Research on text message reminders and goal-focused nudges in other countries has also found that simple reminders can boost savings activity or account usage, especially among inactive users, though results vary by context and medium. (poverty-action.org)
Summary
| Feature | Effect |
|---|---|
| Regular reminder emails | Slightly increases likelihood of one-time savings deposits (≈0.5%–1.3% increase) (Phys.org) |
| Weekly tailored messages | Most effective format tested (Knowledge at Wharton) |
| Personalized calls to action | Helps reduce friction to saving (Kellogg Insight) |
| Collective impact | Can meaningfully increase total savings at scale (Kellogg Insight) |
Bottom Line
Regular email reminders serve as inexpensive but effective behavioral nudges that help bank customers remember to save — especially when the emails are frequent, personalized, and include clear actions. While the effect on each individual is modest, the cumulative impact across millions of people can be significant. (Phys.org)
Here are detailed case studies and expert comments showing how regular email reminders (and similar nudges) help bank customers save more money — with real evidence, results, and perspectives from behavioral science research:
Case Study 1 — Two-Million-Person Megastudy (U.S. Bank)
Overview
A major study led by Katy Milkman and colleagues tested whether regular, behaviorally designed email reminders could increase savings among nearly 2 million customers of a large U.S. bank. This is one of the largest experiments ever conducted on savings behavior. (OUP Academic)
Design
- Bank customers were randomly assigned to receive one of seven different email campaigns or no emails at all. (OUP Academic)
- Emails varied by frequency (weekly vs. monthly), timing, and content (e.g., reminders vs. congratulations). (OUP Academic)
Key Results
- On average, receiving an email increased the likelihood of making a one-time savings transfer by 0.05 percentage points (~0.5% increase). (OUP Academic)
- The best-performing campaign was weekly tailored emails:
- Customers who hadn’t saved recently got a simple reminder to save.
- Customers who had saved recently got a congratulatory message.
- This increased monthly savings likelihood by 1.32% — significantly stronger than other emails. (OUP Academic)
- Extrapolated across the study population, this intervention could generate $6.1 M to $9.9 M in additional savings over two months. (OUP Academic)
Behavioral Insights
- Frequent reminders help overcome forgetfulness, a major barrier to saving. (Knowledge at Wharton)
- Congratulatory messaging reinforces positive habits by giving psychological rewards. (Knowledge at Wharton)
- However, the emails didn’t increase automatic monthly transfers, possibly because the bank’s app didn’t support easy setup — highlighting how friction matters for long-term behavior change. (Knowledge at Wharton)
Comment from the researchers:
“One of the biggest barriers to behavior change is simply that these tasks are not top of mind… reminders give people a small push to follow through.” — Katy Milkman, Wharton Professor. (Knowledge at Wharton)
Case Study 2 — Behavioral Science and Communication Design
Although not strictly a banking case study, related research shows how message design and frequency affect savings behavior:
Workplace Savings Reminder Experiment
- A financial services firm tested weekly email savings prompts tied to employee paydays — part of an “Autumn Savings Festival.” (Common Cents Lab Finsights Guide)
- Participants were randomly assigned different reminder days and motivational incentives (like lottery entries). (Common Cents Lab Finsights Guide)
- Results: Over 20% of participants reported making at least one savings contribution during the campaign, with total savings above $18,600 across the group. (Common Cents Lab Finsights Guide)
- Takeaway: Regular, structured reminders — especially when tied to real financial moments like paydays — can motivate action. (Common Cents Lab Finsights Guide)
Related Evidence — SMS/Text Message Reminder Studies
Though focused on text messaging (another reminder medium), these studies reinforce the nudge logic behind regular reminders:
Global Evidence (IPA Studies)
- In Peru, reminders led inactive clients to transact more (though this did not always translate into higher total savings). (poverty-action.org)
- In Ghana and the Philippines, simple reminder messages increased account use but didn’t consistently lead to more savings. (poverty-action.org)
These variations suggest that reminders tend to boost engagement, but conversion to actual saving may depend on context, message design, and ease of action — similar themes seen in email studies. (poverty-action.org)
Expert Comments & Interpretation
From Behavioral Scientists
- Reminders counter forgetting. A core behavioral barrier is that people intend to save but simply don’t remember — reminders reduce this intention-action gap. (Knowledge at Wharton)
- Frequency matters. Weekly reminders tend to outperform monthly ones because they keep savings top-of-mind more consistently. (Kellogg Insight)
- Positive reinforcement works. Congratulatory messages tap into psychological rewards and can motivate repeat behavior. (OUP Academic)
Comment from Researchers
“Email was the easiest communication channel to test, but also the easiest to ignore… future work could explore more engaging channels and combine reminders with automatic features.” — Lead study authors. (Knowledge at Wharton)
What This Means for Banks & Customers
For Banks
Low-cost intervention: Email campaigns cost almost nothing but can nudge measurable behavior change at scale. (Kellogg Insight)
Segmentation helps: Tailoring messages based on recent saving behavior enhances effectiveness. (OUP Academic)
Design matters: Supporting technical features (like easy recurring transfers) can amplify impact. (Knowledge at Wharton)
For Customers
Gentle reminders aid habit formation — you’re more likely to act when prompted regularly. (Knowledge at Wharton)
Personalized prompts feel more relevant and can reinforce good behavior through positive feedback. (OUP Academic)
Summary of Key Takeaways
| Aspect | Finding |
|---|---|
| Email reminders | Small but meaningful boost in savings actions (0.5%–1.3%) for recipients vs. non-recipients. (OUP Academic) |
| Weekly frequency | Most effective timing relative to monthly or one-off emails. (OUP Academic) |
| Congratulatory content | Reinforces positive behavior and motivates ongoing engagement. (OUP Academic) |
| Design & ease | Impact grows when saving actions are easy to complete. (Knowledge at Wharton) |