NOMO app and teenage social media use: a randomised controlled trial in England and Wales
| ISRCTN | ISRCTN11151579 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN11151579 |
| Protocol serial number | TP2023025 |
| Sponsor | The Behavioural Insights Team |
| Funder | National Endowment for Science Technology and the Arts |
- Submission date
- 31/10/2025
- Registration date
- 18/11/2025
- Last edited
- 27/02/2026
- Recruitment status
- No longer recruiting
- Overall study status
- Ongoing
- Condition category
- Other
Plain English summary of protocol
Background and study aims
This study is looking at whether a smartphone app called NOMO can help teenagers in UK schools use social media less. Research suggests that too much social media can affect young people’s learning, happiness, and sleep. The app encourages pupils to spend less time on their phones by using peer support, shared challenges, and rewards. The study will test how well the app works by comparing schools that use it with schools that don’t.
Who can participate?
Pupils in Years 9 and 10 at participating UK secondary schools can take part. Teachers and parents may also be invited to share their views.
What does the study involve?
Pupils in schools chosen to use the app will be invited to download NOMO and take part in its challenges from November 2025 to March 2026. All pupils will be asked to complete short anonymous surveys before and after the trial, looking at things like how much time they spend on social media, how distracted they feel, how satisfied they are with life, and how well they sleep. Some pupils, teachers, and parents may also be invited to take part in voluntary interviews or extra surveys to share their experiences.
What are the possible benefits and risks of participating?
Using the app may help pupils reduce screen time, feel more focused, sleep better, and feel happier. There are no known risks, but pupils can choose not to take part in any part of the study if they don’t want to. All responses will be kept anonymous.
Where is the study run from?
Behavioural Insights Team (UK)
When is the study starting and how long is it expected to run for?
The study starts in November 2025 and will run until March 2026.
Who is funding the study?
National Endowment for Science Technology and the Arts (UK)
Who is the main contact?
niall.daly@bi.team
Contact information
Scientific
Behavioural Insights Team, Victoria Embankment
London
EC4Y 0DS
United Kingdom
 ORCID ID |
0009-0009-8378-4261 |
|---|---|
| Phone | +44 (0) 207 438 2500 |
| niall.daly@bi.team |
Principal investigator
Behavioural Insights Team, Victoria Embankment
London
EC4Y 0DS
United Kingdom
| Phone | +44 (0) 207 438 2500 |
|---|---|
| lal.chadeesingh@bi.team |
Public
Behavioural Insights Team, Victoria Embankment
London
EC4Y 0DS
United Kingdom
| Phone | +44 (0) 207 438 2500 |
|---|---|
| callum.omahony@bi.team |
Study information
| Primary study design | Interventional |
|---|---|
| Study design | Interventional randomized controlled trial and implementation and process evaluation (IPE) using mixed methods |
| Secondary study design | Randomised controlled trial |
| Scientific title | Changes in social media usage among teenage smartphone users in the UK: a randomised controlled trial of the NOMO app |
| Study acronym | NOMOSM |
| Study objectives | The primary objective of the research is to evaluate the effectiveness of NOMO in reducing social media use in UK schools. This evaluation seeks to generate evidence to inform potential scale-up of the NOMO app, and aims to answer three research questions. The primary research question is: "How effective is the NOMO smartphone app in reducing social media usage of Year 9 and 10 pupils?". The study also seeks to address one secondary research question: "How effective is introducing the NOMO smartphone app in schools, and encouraging pupils to use it, in reducing distraction for Year 9 and 10 pupils?". The study also seeks to address two exploratory research questions: "How effective is the NOMO smartphone app in improving life satisfaction for Year 9 and 10 pupils?"; and "How effective is the NOMO smartphone app in improving the quality of sleep of Year 9 and 10 pupils?" |
| Ethics approval(s) |
Approved 13/10/2025, Behavioural Insights Team internal ethics review (58 Victoria Embankment, London, EC4Y 0DS, United Kingdom; +44 (0) 207 438 2500; info@bi.team), ref: TP2025023 |
| Health condition(s) or problem(s) studied | Social media usage, distraction, life satisfaction, sleep |
| Intervention | Control (comparison arm): The comparison group is a waitlist control arm. Pupils in schools assigned to this arm are expected to continue with their business-as-usual social media practices during the trial period. They will not be invited to use the NOMO app by the research team or their school during the intervention period (November 2025 to February 2026). They receive the intervention (invitation to use the app) only after the trial period ends, starting in March 2026. The total duration of the active intervention for the control group during the study period is zero months, with a three-month follow-up (endline survey in February 2026) Treatment arm: The treatment arm is invited to download and use the NOMO smartphone application. The intervention involves school staff introducing and encouraging all eligible and consenting pupils to download and use the app. The NOMO app uses collective action principles (peer support, shared challenges, positive reinforcement) to help users reduce the time they spend on social media, for example, by earning points redeemable for rewards. The total duration of the active intervention is approximately three months, running from November 2025 to February 2026. Follow-up occurs immediately after the intervention ends, with the endline survey administered in early-mid February 2026. Randomisation process: This study employs a two-arm waitlist design RCT where randomization occurs at the school level (cluster randomisation). All participating pupils within a school are placed in the same trial arm. Once all schools are recruited and have completed their baseline surveys, they will be randomised by the Behavioural Insights Team (BIT) into one of the two trial arms (Treatment or Control). Schools will be randomly allocated to arms using a cluster-level randomisation procedure performed in Stata 16.0 software, with the process secured by a reproducible seed for complete transparency. |
| Intervention type | Behavioural |
| Primary outcome measure(s) |
Social media usage measured using a self-report 9-point scale questionnaire item at baseline (November 2025) and endline (February 2026). The specific item wording is: “Thinking about your last full school day, how much time in total do you think you spent using social media apps (like TikTok, Instagram, etc.) over the entire 24-hour day?” |
| Key secondary outcome measure(s) |
1. Distraction is measured using a self-report 7-point Likert scale questionnaire item, adapted from the Online Homework Distraction Scale (ODHS) at baseline (November 2025) and endline (February 2026). The specific item wording is: “I stop my homework to check my social media (e.g., Instagram, TikTok)". |
| Completion date | 07/03/2026 |
Eligibility
| Participant type(s) | Learner/student |
|---|---|
| Age group | Child |
| Lower age limit | 12 Years |
| Upper age limit | 16 Years |
| Sex | All |
| Target sample size at registration | 14000 |
| Key inclusion criteria | Being a Year 9 or Year 10 pupil in a participating UK secondary school |
| Key exclusion criteria | Withdrawal from the evaluation by a parent or guardian |
| Date of first enrolment | 03/11/2025 |
| Date of final enrolment | 14/11/2025 |
Locations
Countries of recruitment
- United Kingdom
- England
- Wales
Study participating centres
Garrison Lane
Surrey
KT9 2JS
England
Ilford
IG2 7BT
England
Selsey
Chichester
PO20 9EH
England
London
N14 7HY
England
Gloucester
GL1 5LE
England
Barking
IG11 9AG
England
53-55 High Street
Feltham
TW13 4AB
England
Kennington
Ashford
TN24 9AL
England
Ebbw Vale
Blaenau Gwent
NP23 6GL
Blaenau Gwent
NP23 6GL
Wales
Barrow-in-furness
LA13 0NY
England
Groby
Leicester
LE6 0FP
England
Stevenage
SG2 8UT
England
Cramlington
NE23 6BN
England
Gosport
PO13 0JN
England
Cardiff
South Glamorgan
CF24 2YE
Cardiff
CF24 2YE
Wales
Barton-upon-humber
DN18 6AE
England
Halifax
HX2 9TZ
England
Romiley
Stockport
SK6 3BX
England
Leytonstone
E11 3NN
Leytonstone
E11 3NN
England
Lichfield
WS13 7EW
England
Liverpool
L6 7UR
Liverpool
L6 7UR
England
Brookmans Park
Hatfield
AL9 7BN
England
Vale of Glamorgan
CF71 7EN
Wales
Clacton-on-sea
CO15 6DZ
England
Grimsby
DN32 8JH
England
Alsager
Stoke-on-trent
ST7 2HR
England
Poplar
London
E14 0RZ
England
Dibden Purlieu
Southampton
SO45 4RQ
England
Surrey
GU1 2TN
England
Hounslow
TW3 4EP
England
Poole
BH15 4BQ
England
Coventry
CV6 2AJ
England
Wellington
TA21 8SW
England
Chorley
PR7 3AY
England
Hereford
HR1 1UU
England
Enfield
EN2 6QG
England
Liverpool
L11 9DQ
England
Solihull
B91 2HW
England
Sefton Park
Liverpool
L17 3AL
England
Marlow
SL7 2BR
England
Sheffield
S20 1HQ
England
London
SW12 0AB
England
Congleton
CW12 1NT
England
Gravesend
DA12 4LF
England
Rugby
CV22 6EA
England
Chingford
London
E4 8ES
England
Woking
Surrey
GU22 9AL
England
Newport
NP19 4RP
Wales
London
NW9 4AS
England
Middleton
Manchester
M24 2GT
England
Rubery
Rednal
Birmingham
B45 9EL
England
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|---|
| IPD sharing plan summary | Not expected to be made available |
| IPD sharing plan |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Protocol file | 10/11/2025 | No | No |
Additional files
Editorial Notes
27/02/2026: The completion date was changed from 28/02/2026 to 07/03/2026.
03/11/2025: Trial's existence confirmed by Behavioural Insights Team.
