How The Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine (MRCG at LSHTM) used SurveyCTO's ACASI features to capture sensitive data
Meet The Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine (MRCG at LSHTM)
The London School of Hygiene & Tropical Medicine is a public research university in the United Kingdom specializing in public and global health, epidemiology and tropical medicine. They have three main hubs located in the UK, Uganda, and The Gambia focused on research and creating a more healthy, sustainable and equitable world.
The Medical Research Council Unit The Gambia (MRCG) at LSHTM in particular, leads medical research and clinical trials in West Africa with the goal of improving health outcomes in the region and around the world.
Offices: Fajara, The Gambia
Sector: Healthcare
Use case: Global health
Features used: ACASI, data encryption, multi-lingual support, audio and image support
Website: https://www.lshtm.ac.uk/research/units/mrc-gambia
The Challenge: Gathering accurate, complete, sensitive sexual health data in The Gambia
Measuring sexual behavior through surveys can be challenging. This is especially so in parts of the world like The Gambia due to cultural norms and values around sexuality—especially for women. Social desirability bias is a particularly common survey challenge in such contexts, leading to the underreporting of sexual behavior that can directly correlate to the prevalence estimates of sexually-transmitted infections (STIs).
Despite these challenges, it remains vitally important to public health in the country to capture this sensitive data on the prevalence of STIs to understand how they are acquired and spread.
With this objective in mind, the MRCG Unit implemented a large-scale, cross-sectional, population-based study (PHASE survey) of women aged 15 to 49 years old to assess the prevalence of human papillomavirus (HPV), antimicrobial resistance (AMR), and other sexually transmitted infections (STIs).
Reducing social desirability bias and collecting accurate, complete data was, of course, a great concern and major focus for the MRCG Unit as they prepared to roll out the PHASE survey in this area. The research team knew that they would need to employ innovative survey methods to achieve their objective of high-quality data and ultimately, well-informed health policies.
The Solution: Using the ACASI survey method for self-administered data collection
One barrier to traditional CAPI (Computer-Assisted Personal Interview) methods in situations like the PHASE survey is simply the presence of enumerators who are required to administer the survey. In The Gambia, asking questions about sexual behavior outside of medical contexts is considered extremely intrusive and inappropriate—especially for women, who were the sole sample for the PHASE survey.
To solve this challenge, the MRCG Unit explored the Audio-Computer Assisted Self-Interview (ACASI) method.
ACASI surveys involve respondents answering pre-recorded survey questions on their own digital devices or computers. Answers are selected via a touchscreen or keyboard. This setup allows for maximum privacy and safety for the respondent, letting them complete the survey in their own homes at times most convenient to them.
Because no enumerators are present to potentially influence respondent answers, social desirability bias has been shown to be much reduced in ACASI surveys, making them ideal for sensitive questionnaires like the PHASE survey.
Beyond helping to reduce social desirability bias, ACASI provided another advantage for this study. In the area where the PHASE study is being conducted, four languages are predominantly spoken: Mandinka, Serahule, Fula, and Wolof. None of these languages is widely written, and the literacy rate for Gambian women is about 47%. Given these restraints, this alternative survey format, where questions are listened to instead of read, was a natural fit.
Through careful piloting and testing, the research team at the MRCG Unit deduced that despite some initial technical challenges, the ACASI method was indeed well-suited to meet the needs of the PHASE survey. Once they established that they would use ACASI, the MRCG Unit then needed to select a data collection tool that provided this functionality.
Inspired by previous usage of the SurveyCTO platform as an ACASI platform for a sensitive survey in Uganda in 2021, they chose SurveyCTO for the PHASE survey.
In addition to fully supporting ACASI, other SurveyCTO features were also instrumental in the PHASE survey:
- Image and audio inclusion: In order to make respondents comfortable and provide maximum privacy, the MRCG Unit used familiar and non-threatening images—like teapots, motorcycles, common foods, and other everyday items in The Gambia unrelated to the actual questions—in the PHASE survey. Survey questions were also pre-recorded on audio for respondents to listen to during the actual survey to eliminate the need for enumerators.
- Multi-language support: As mentioned, four languages are predominantly spoken in this region, making SurveyCTO’s multi-lingual support—which is fully compatible with ACASI—invaluable in this survey.
- End-to-end encryption: Respondent privacy was of great importance to the PHASE survey given the cultural sensitivity of its subject matter. SurveyCTO offers some of the most advanced data protection options for survey platforms, including end-to-end survey encryption. The MRCG Unit used this feature to ensure that PHASE data was always protected from unauthorized access when at rest or in transit. Details about the confidentiality of the survey were also included in its introduction to help reassure respondents and boost data quality.
See the ACASI workflow below in multiple languages
The MRCG Unit used SurveyCTO’s ACASI features for the PHASE study. Watch this video to see the workflow in action on SurveyCTO Collect. (English language.)
The MRCG Unit used SurveyCTO’s ACASI features for the PHASE study. Watch this video to see the workflow in action on SurveyCTO Collect. (Wollof language.)
The MRCG Unit used SurveyCTO’s ACASI features for the PHASE study. Watch this video to see the workflow in action on SurveyCTO Collect. (Mandinka language.)
The MRCG Unit used SurveyCTO’s ACASI features for the PHASE study. Watch this video to see the workflow in action on SurveyCTO Collect. (Serahule language.)
The MRCG Unit used SurveyCTO’s ACASI features for the PHASE study. Watch this video to see the workflow in action on SurveyCTO Collect. (Fula language.)
The ACASI tool for this survey was developed together with a Community Advisory Board (CAB) that was created by the MRCG team. The CAB is composed of local women and men from communities in The Gambia.
The MRCG Unit also extensively piloted the survey instrument and made refinements to their original questions based on findings from the pilot, such as adding new instructions to the beginning of the survey to help respondents who were new to digital tools successfully navigate the questionnaire.
The results
To the MRCG Unit’s knowledge, the PHASE survey is the first time ACASI has been used in The Gambia, or in an STI prevalence survey of this magnitude anywhere in West Africa, representing a unique achievement for survey research in the area.
As of September 2025, the PHASE survey has collected responses from a sample of nearly 10,000 women. Additionally, despite unfamiliarity with digital tools, cultural conservatism around sexuality, and low literacy rates, only ~1% of respondents have been unable to complete the survey.
While the PHASE survey is still ongoing, with final results expected by mid-2026, this significantly high completion rate is very promising. For the team at the MRCG Unit, this survey has shown that with the right digital tools, cultural sensitivity, preparation, and involvement of the local community, ACASI can be an incredibly effective instrument for sensitive data collection in this region, and SurveyCTO has the functionality to make this survey method possible.
