Condition category
Not Applicable
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
The majority of smokers want to stop smoking and many try to quit each year, but success rates are low. Methods of supporting smokers during a quit attempt that are low-cost and easy to access are needed. We are hoping to find out how likely smokers who are motivated to quit are to be successful in quitting, and how far this is influenced by how they try to quit. Specifically, we want to know whether offering a smoker a popular smartphone app can increase their chances of quitting successfully.

Who can participate?
People are eligible to take part in this study if they are aged 18 years or older, are able to provide informed consent, are an English speaker, own a smartphone, are a current cigarette smoker, are willing to be followed-up by email and complete four brief questionnaires after 1, 4 and 7 months and are interested in making a quit attempt in the next 30 days.

What does the study involve?
Participants will be asked to complete four brief online questionnaires: now, and in 1, 4 and 7 months’ time. The first questionnaire is the longest, and will take around 10 minutes to complete. The other three are shorter and will take around 3-5 minutes. We will send an email to let them know when it is time to complete each survey.

What are the possible benefits and risks of participating?
Participating in the study will help us to understand more about how different tools can be used to help people quit smoking, making a valuable contribution to science and public health. On behalf of those who complete all four surveys we will make a £10 donation to Cancer Research UK or Macmillan Cancer Support, according to the participant's preference. We do not anticipate any problems related to participation in this study.

Where is the study run from?
University College London (UK). More information about the study team can be found at

When is the study starting and how long is it expected to run for?
August 2018 to March 2022

Who is funding the study?
This study is part of a large programme of work funded by Cancer Research UK (UK)

Who is the main contact?
Dr Sarah Jackson,
Prof. Jamie Brown,

Trial website

Contact information



Primary contact

Dr Sarah Jackson


Contact details

1-19 Torrington Place
United Kingdom
+44 (0)207 6795616



Additional contact

Prof Jamie Brown


Contact details

1-19 Torrington Place
United Kingdom
+44 (0)207 6795616

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number


Study information

Scientific title

Effectiveness of an offer of the Smoke Free smartphone application for smoking cessation compared with no support: the App for Smoking ceSsation Evaluation Trial (ASSET)



Study hypothesis

In English‐speaking adult smokers willing to quit in the next 4 weeks who are recruited online or have previously used the Smoke Free app and agreed to be followed‐up and in an unrestricted setting, an offer to use the app plus follow‐up (intervention) will increase self‐reported smoking cessation for at least 26 weeks, assessed 30 weeks after enrolment, compared with no offer of the app and follow‐up only (comparator).

Ethics approval

Approved 06/09/2019, UCL Research Ethics Committee (University College London, 2 Taviton St, London WC1E 6BT, UK. +44 (0)207 6798717;, ref: CEHP/2016/556

Study design

Interventional randomized controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet


Smoking cessation


This will be a two‐arm individually randomized controlled effectiveness trial. Participants will be adult smokers who are intending to quit in the next 4 weeks, willing to participate in a 30‐week study of their smoking and able to provide consent.

Those who are eligible and consent to participate in the trial will be randomized at that point to intervention or comparator conditions. Randomization will be 1:1 at the individual level with no restriction (i.e. no blocking) and will be automated using a random number function.

After consenting, participants in the comparator condition will receive a message encouraging them to make a quit attempt within the next 4 weeks and reminding them of the importance of responding to follow‐up requests which are designed to track their progress.

Participants in the intervention condition will receive the same advice as those in the comparator condition plus offer of the full version of the Smoke Free app free of charge, encouragement to use the app and a link to download it. The Smoke Free app is based on behaviour change techniques that would be expected from theory and evidence with face‐to‐face support to aid smoking cessation. It guides smokers through the first month of their quit attempt by helping them to maintain their resolve by setting a clear goal, monitoring their progress towards that goal and becoming aware of benefits of being smoke‐free achieved to date. The app has several components:
1. A calculator which tracks the total amount of money not spent on buying cigarettes and the number of cigarettes not smoked (‘Dashboard')
2. A calendar which tracks the amount of time elapsed since cessation (‘Dashboard')
3. A scoreboard which awards virtual ‘badges' to users for not smoking (‘Badges')
4. Progress indicators which inform users of the health improvements made since the start of their quit attempt (e.g. pulse rate, oxygen levels, carbon monoxide levels; ‘Dashboard')
5. A diary which tracks the frequency, strength, location and triggers of cravings to smoke (‘Diary')
6. A graph which displays the frequency, location, strength and triggers of cravings to smoke (‘Cravings')
7. Daily missions which are assigned from the start of a user's quit date for one calendar month (‘Missions')
8. A chatbot which delivers evidence‐based guidance about quitting smoking via a conversational interface which resembles text messaging (‘Chatbot')
9. 24/7 online expert support

The investigators will be blinded to participants' treatment allocation until all data have been collected.

Intervention type



Not Applicable

Drug names

Smoke Free app

Primary outcome measure

Self‐reported smoking cessation for at least 26 weeks, assessed 30 weeks after enrolment

Secondary outcome measures

Assessed using self report:
1. Having made at least one quit attempt in the 4 weeks following enrolment in the study
2. Smoking cessation for at least 12 weeks, assessed 4 weeks after enrolment
3. Downloading or using the Smoke Free app at least once, assessed 30 weeks after enrolment

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Aged at least 18 years
2. Able to provide consent
3. English speaker
4. Owns a smartphone
5. Current cigarette smoker
6. Willing to be followed‐up by e‐mail and complete online questionnaires after 1, 4 and 30 weeks
7. Interested in making a quit attempt within the next month

Participant type

Healthy volunteer

Age group




Target number of participants


Participant exclusion criteria

1. Used the Smoke Free app in the past 6 months

Recruitment start date


Recruitment end date



Countries of recruitment

Afghanistan, Aland Islands, Albania, Algeria, American Samoa, Andorra, Angola, Anguilla, Antarctica, Antigua and Barbuda, Argentina, Armenia, Aruba, Australia, Austria, Azerbaijan, Bahamas, Bahrain, Bangladesh, Barbados, Belarus, Belgium, Belize, Benin, Bermuda, Bhutan, Bolivia, Bonaire Saint Eustatius and Saba, Bosnia and Herzegovina, Botswana, Bouvet Island, Brazil, British Indian Ocean Territory, Brunei, Bulgaria, Burkina Faso, Burundi, Cambodia, Cameroon, Canada, Cape Verde, Cayman Islands, Central African Republic, Chad, Chile, China, Christmas Island, Cocos (Keeling) Islands, Colombia, Comoros, Congo, Congo, Democratic Republic, Cook Islands, Costa Rica, Cote d'Ivoire, Croatia, Cuba, Curacao, Cyprus, Czech Republic, Denmark, Djibouti, Dominica, Dominican Republic, Ecuador, Egypt, El Salvador, Equatorial Guinea, Eritrea, Estonia, Ethiopia, Falkland Islands, Faroe Islands, Fiji, Finland, France, French Guiana, French Polynesia, French Southern Territories, Gabon, Gambia, Georgia, Germany, Ghana, Gibraltar, Greece, Greenland, Grenada, Guadeloupe, Guam, Guatemala, Guernsey, Guinea, Guinea-Bissau, Guyana, Haiti, Heard Island and Mcdonald Islands, Holy See (Vatican City State), Honduras, Hong Kong, Hungary, Iceland, India, Indonesia, Iran, Iraq, Ireland, Isle of Man, Israel, Italy, Jamaica, Japan, Jersey, Jordan, Kazakhstan, Kenya, Kiribati, Korea, North, Korea, South, Kosovo, Kuwait, Kyrgyzstan, Laos, Latvia, Lebanon, Lesotho, Liberia, Libya, Liechtenstein, Lithuania, Luxembourg, Macao, Macedonia, Madagascar, Malawi, Malaysia, Maldives, Mali, Malta, Marshall Islands, Martinique, Mauritania, Mauritius, Mayotte, Mexico, Micronesia, Federated States of, Moldova, Monaco, Mongolia, Montenegro, Montserrat, Morocco, Mozambique, Myanmar, Namibia, Nauru, Nepal, Netherlands, Netherlands Antilles, New Caledonia, New Zealand, Nicaragua, Niger, Nigeria, Niue, Norfolk Island, Northern Mariana Islands, Norway, Oman, Pakistan, Palau, Palestinian Territory, Panama, Papua New Guinea, Paraguay, Peru, Philippines, Pitcairn, Poland, Portugal, Puerto Rico, Qatar, Reunion, Romania, Russian Federation, Rwanda, Saint Barthelemy, Saint Helena, Saint Kitts and Nevis, Saint Lucia, Saint Martin (French part), Saint Pierre and Miquelon, Saint Vincent and the Grenadines, Samoa, San Marino, Sao Tome and Principe, Saudi Arabia, Senegal, Serbia, Seychelles, Sierra Leone, Singapore, Sint Maarten (Dutch part), Slovakia, Slovenia, Solomon Islands, Somalia, South Africa, South Georgia and the South Sandwich Is, South Sudan, Spain, Sri Lanka, Sudan, Suriname, Svalbard and Jan Mayen, Swaziland, Sweden, Switzerland, Syria, Taiwan, Tajikistan, Tanzania, Thailand, Timor-Leste, Togo, Tokelau, Tonga, Trinidad and Tobago, Tunisia, Turkey, Turkmenistan, Turks and Caicos Islands, Tuvalu, Uganda, Ukraine, United Arab Emirates, United Kingdom, United States Minor Outlying Islands, United States of America, Uruguay, Uzbekistan, Vanuatu, Venezuela, Viet Nam, Virgin Islands, British, Virgin Islands, U.S., Wallis and Futuna, Western Sahara, Yemen, Zambia, Zimbabwe

Trial participating centre

University College London
1-19 Torrington Place
United Kingdom

Sponsor information


University College London

Sponsor details

2 Taviton St
United Kingdom
+44 (0)20 7679 8717

Sponsor type




Funder type


Funder name

Cancer Research UK

Alternative name(s)


Funding Body Type

private sector organisation

Funding Body Subtype

Other non-profit organizations


United Kingdom

Results and Publications

Publication and dissemination plan

Planned publication in a peer-reviewed journal.

IPD sharing statement:
The datasets generated during and/or analysed during the current study will be stored in a publically available repository. (Open Science Framework, Anonymised data will be shared without restriction upon submission of the trial report to a peer-reviewed journal.

Intention to publish date


Participant level data

Stored in repository

Basic results (scientific)

Publication list

2019 protocol in: (added 08/10/2020)

Publication citations

Additional files

Editorial Notes

07/01/2021: The target number of participants was changed from 1,733 to 3,116. 20/10/2020: Internal review. 15/10/2020: Trial’s existence confirmed by Cancer Research UK.