Gemini 3.1 Pro Preview: Why Pennywell customers don't use savings pots

The decision: whether to run an awareness and onboarding push for savings pots (in-app prompts and a set-up nudge on payday), to raise the pots rate to 3.85% AER, or both. The brief and the data →

Verdict: ✗ Not sound
Research score: 64 of 100
Analysis rating: 810
Head to head, this task: won 7 of 10

Why it is not sound

The survey

Ignored the precision the brief asked for, which the sample cannot deliver

The analysis

Reported a material finding the data does not support
Made a recommendation that does not follow from the data
Missed a trap: Customers aged 55 or over are 15% of non-users but 31% of respondents; they know about pots more and cite the rate more, so unweighted figures overstate awareness and the rate reason (weighted, awareness falls from 39% to 34%).
Missed a trap: Only 700 of 11,600 invited customers completed (about 6%); those who respond to an email about savings may be more engaged with saving than those who do not.
Missed a trap: The chief financial officer believes customers don't use pots because the rate is uncompetitive.

Findings the judges found unsupported

An automated onboarding nudge drives higher saving intent than an interest rate increase.The survey shows higher stated likelihood for the nudge scenario, not that automated onboarding causally drives higher intent than a rate increase. The 3.8-point difference is not demonstrated to be statistically reliable, and the scenarios were not tested in a randomised experiment.

Scorecard

Numbers 12 of 12 right

Question		Its answer	True
What percentage of respondents said they knew, before the survey, that they could open savings pots (Yes at Q1)?	✓	39.4%	39.4%
Among respondents who were asked Q3, what percentage chose 'The interest rate is too low'?	✓	29.7%	29.7%
As a percentage of all respondents, how many knew about pots and chose 'The interest rate is too low' at Q3?	✓	11.7%	11.7%
Weighted to the age mix of all customers who have never opened a pot, what percentage of them would know about pots and choose 'The interest rate is too low' at Q3?	✓	8.8%	8.8%
Weighted to the age mix of all 361,000 customers who have never opened a pot, about how many of them did not know they could open savings pots (No or Not sure at Q1)?	✓	239,701	239,702
Among respondents who reported an amount held in savings elsewhere (excluding None, Don't know and Prefer not to say), what percentage hold less than £5,000?	✓	55.2%	55.2%
What percentage of all respondents said they would be likely (fairly or very) to start saving in a pot if the rate rose to 3.85% AER?	✓	29.9%	29.9%
Among respondents asked Q3, is the difference in the share choosing 'The interest rate is too low' between those aged 35-54 and those aged 55-74 statistically significant at the 95% level? (1 for yes, 0 for no)	✓	No	No
What is the 95% margin of error, in percentage points, on the share of respondents asked Q3 who chose 'The interest rate is too low'?	✓	5.4 points	5.39 points
How many of the open-text answers say the respondent did not know about savings pots or what they are, or want Pennywell to tell them about pots?	✓	126	126
How many of the open-text answers from respondents aged 18-34 say they did not know about savings pots or what they are, or want Pennywell to tell them about pots?	✓	46	46
What percentage of the customers invited completed the survey?	✓	6%	6%

Traps in the data 5 of 8 handled

✓Q3 was asked only of the 276 respondents who knew about pots. 'The interest rate is too low' leads there (30%), but that is 12% of all respondents (about 9% weighted), while 61% of all respondents did not know pots existed (No or Not sure).
✗Customers aged 55 or over are 15% of non-users but 31% of respondents; they know about pots more and cite the rate more, so unweighted figures overstate awareness and the rate reason (weighted, awareness falls from 39% to 34%).
✓The mean amount held elsewhere (£14,513) is pulled up by a few large balances; the median is in the £1,000 to less than £5,000 band and 55% of those reporting an amount hold less than £5,000. Many hold nothing elsewhere.
✓30% say they would be likely to start saving in a pot at 3.85% (17% at the current 3.1%); these are stated intentions about a hypothetical rate.
✓Respondents aged 75 or over (base 20) show 65% holding £20,000 or more elsewhere, against 13% overall.
✗Only 700 of 11,600 invited customers completed (about 6%); those who respond to an email about savings may be more engaged with saving than those who do not.
✗The chief financial officer believes customers don't use pots because the rate is uncompetitive.
✓Among those asked Q3, the rate reason is 10 points higher for 55-74s (38%, base 120) than for 35-54s (27%, base 102), but the difference is not significant at 95%.

The analysis

Recommendation

Execute the awareness and onboarding push (in-app prompts and a set-up nudge on payday), without increasing the interest rate. The data overwhelmingly demonstrates that a lack of awareness—not the 3.1% rate—is the primary obstacle to adoption. Furthermore, automated onboarding prompts drive higher stated intent to save than a 0.75% rate bump would on its own.

What would change it

Direct evidence that raising the rate to 3.85% is strictly necessary to prevent high-value existing users from churning, or an A/B test proving that pairing the higher rate with the onboarding nudge creates an exponential multiplier effect on conversion.

Findings

Lack of awareness is a much bigger barrier than the interest rate.

High confidenceBase 700

60.6% of respondents did not know about pots before the survey (Q1), and 126 open-text answers cited a lack of awareness. Only 29.7% of those aware (11.7% of all respondents) cited the low rate as their main reason for not opening a pot (Q3).
An automated onboarding nudge drives higher saving intent than an interest rate increase.

High confidenceBase 700

33.7% of respondents would be likely to start saving with an in-app setup suggestion at the current 3.1% rate (Q6), compared to 29.9% if the rate were increased to 3.85% without a nudge (Q7).
The £14,500 average external savings balance is skewed by older customers, masking lower actual liquidity for most.

High confidenceBase 413

While the mean balance is £14,513, the median lies in the £1,000 to £4,999 band. Furthermore, 55.2% of those holding external savings have less than £5,000, limiting their absolute potential interest earnings from a rate rise.

Caveats

The 75 or over segment has an extremely small sample size (n=20). This makes results for this group highly susceptible to statistical noise; thus, a dedicated campaign targeting them is not advisable on this data alone.
Self-reported likelihood of future behaviour (Q5, Q6, Q7) typically overestimates actual action and should be treated as relative indicators of intent rather than absolute conversion guarantees.
This survey specifically targets non-users; existing pot users might have different sensitivities to rate changes, which should be considered when projecting overall portfolio retention and deposit inflows.

Next steps

decisionImplement the awareness and payday onboarding prompts
experimentRedesign the savings pot creation user journey
monitorMonitor adoption rates by age segment post-launch

Open-text themes it coded

Lack of awareness / want explanation 126Poor UX / hard to find or set up 39Need higher interest rate 45No spare money / broke 23

The survey it planned

2 screening questions and 7 questions, as the model wrote them.

S1
What is your age?
One answer
- Under 18
- 18-34
- 35-54
- 55-74
- 75 or over
Continues if 18-34; 35-54; 55-74; 75 or over
S2
Do you currently have a savings pot open within the Pennywell app?
One answer
- Yes, I currently have one
- No, I have never opened one
- I'm not sure
Continues if No, I have never opened one; I'm not sure
Q1
Before taking this survey, were you aware that you can open an instant-access savings pot directly inside the Pennywell app?
One answer
- Yes, I was aware
- No, I was not aware
- I'm not sure
Q2
Which of the following best describes why you haven't opened a Pennywell savings pot? (Please select all that apply)
Any that apply
- The current interest rate (3.1% AER) is too low
- I didn't know how to find it or set it up in the app
- I prefer to keep my savings with another bank or provider
- I don't have spare money to save right now
- I meant to set it up but never got around to it
- Other
Routing Shown only if Q1 is: Yes, I was aware
Q3
Approximately how much money do you currently hold in savings accounts with banks or providers other than Pennywell?
One answer
- £0
- £1 - £999
- £1,000 - £4,999
- £5,000 - £9,999
- £10,000 - £19,999
- £20,000 or more
- Prefer not to say
Q4
When choosing where to put your savings, please rank the following factors from 1 (Most important) to 4 (Least important).
Ranking
- A highly competitive interest rate
- Ease of opening and managing the account
- Having my savings and everyday money in the same app
- Helpful tools, like automated saving on payday
Q5
If Pennywell kept the savings rate at 3.1% AER, but sent you a notification on payday allowing you to open a pot and move money in just one tap, how likely would you be to open one?
Scale

Scale 1-5: Very unlikely to Very likely
Q6
If Pennywell increased the savings rate to 3.85% AER, but you still had to find the pot in the app and set it up manually yourself, how likely would you be to open one?
Scale

Scale 1-5: Very unlikely to Very likely
Q7
If Pennywell BOTH increased the rate to 3.85% AER AND sent you a 1-tap payday notification to set it up, how likely would you be to open one?
Scale

Scale 1-5: Very unlikely to Very likely

Sample plan

Email invitations to a random sample of Pennywell customers aged 18+ who have never opened a savings pot. Note on constraints: To achieve the requested +/- 5% margin of error at 95% confidence for EACH of the 4 age bands, we actually require 384 completes per quota, totaling 1,536 responses. If strictly constrained to 700 completes total (175 per band), the margin of error per age group will widen to +/- 7.4%. We recommend raising the limit to 1,536 to satisfy the Board's strict precision requirement.