Why the right survey method depends on the target population
A survey covering parts of Cabo Verde may be collected on tablets, through interviewer-led calls or through online forms, but these modes do not create equivalent samples automatically. The study team must decide what counts as an eligible respondent, which contact frames exist and which subgroups might be left out. Comparing Praia with Mindelo is useful because the capital on Santiago with government and consumer services contrasts with a major centre on São Vicente with a different island economy. The final method should follow the research objective, not the other way around.
Before selecting technology, clarify what decision the study will support. A programme assessing actual facility access may require physical observation; a business following up known clients may have usable telephone contacts; a professional survey may rely on verified electronic invitations. Identify the sampling unit, intended geographic coverage, minimum subgroup precision and acceptable burden. Compare modes against these requirements rather than assuming that smartphones make every population equally reachable. A successful data collection method produces valid evidence, not simply a large file.
CAPI: when in-person digital interviewing is strongest
Computer-Assisted Personal Interviewing, or CAPI, uses an interviewer carrying a programmed tablet or smartphone. It is especially useful when selected households, businesses, facilities or physical assets must be visited and verified. A well-programmed form can route questions, enforce reasonable ranges and capture time or location checks where justified. Offline collection can help where mobile data is unreliable, although the team still needs a secure synchronisation plan. Costs include travel, enumerator time, supervision, field permissions and safe access; the highest-cost method may nevertheless provide the strongest coverage.
CATI: when interviewer-led telephone surveys fit
Computer-Assisted Telephone Interviewing, or CATI, permits a trained interviewer to administer questions by voice using a calling system or structured digital form. It can be suitable for beneficiaries with verified contact records, existing customers, business contacts and rapid follow-up studies. The major risks are unreachable numbers, shared phones, unequal ownership and short respondent attention spans. A reliable CATI protocol defines call attempts at different times, dispositions, appointments, refusals and consent for any recording. A random collection of available mobile numbers is not automatically a representative national sample.
CAWI: when self-completed online surveys are credible
Computer-Assisted Web Interviewing, or CAWI, sends eligible respondents to a self-completed online questionnaire. It is effective for digitally reachable users, company staff, verified consumer panels and some professional or student populations. It can lower fieldwork cost and present consistent visual stimuli, but the recruitment source determines the meaning of the results. An open social-media link cannot support a national probability claim. Protect the survey from repeated submissions, fraudulent profiles, inattentive completion and poor mobile display. Accessible wording and a short pilot are essential because no interviewer is present to clarify confusion.
Use the administrative research geography of Cabo Verde
A location frame in Cabo Verde should use the relevant geographic structures, such as municipalities spread across islands, rather than importing another country’s local government labels. The frame should distinguish where people live, work and access services from the administrative boundary used for supervision. A district or municipality may help organise field assignments without supplying a complete list of eligible respondents. Verify any boundaries and contact sources with field teams before sampling. These decisions affect who can enter the CAPI sample, which calling lists may be credible for CATI, and whether a CAWI panel covers the intended area. Island geography can make both travel routes and the reach of phone or online frames highly uneven. Sample designs should explicitly distinguish island populations and avoid interpreting two centres as a national cross-section.
Build a defensible sample before selecting devices
A questionnaire may be identical across modes while the achieved populations are not. Face-to-face routes can underrepresent workers absent during the day; phone frames may miss those without working numbers; web invitations can overrepresent connected or enthusiastic users. The design must identify these risks beforehand. Record initial selection probabilities where known, contact outcomes and subgroup gaps. Weighting can correct some measured imbalances only under defensible assumptions; it cannot manufacture coverage for an excluded population. Study conclusions should clearly name the actual survey universe.
Applying CAPI, CATI and CAWI in Praia
In Praia, the local research environment includes the capital on Santiago with government and consumer services. A household livelihood or service-access survey might use mapped clusters and CAPI where the team must visit selected addresses, verify assets or record in-person observations. A CATI follow-up could be considered when respondents have willingly provided functioning numbers, while CAWI may suit a separately defined digitally reachable subgroup. These methods must not be substituted casually: each can select a different type of participant. Pilot questions and contact procedures within selected neighbourhoods before calculating the city estimate.
Applying CAPI, CATI and CAWI in Mindelo
In Mindelo, the team should independently assess who can be recruited and how, taking account of its character as a major centre on São Vicente with a different island economy. Check whether the listed households or users can be visited safely, whether sufficient valid numbers exist and whether online recruitment would exclude relevant communities. If a mode used in Praia proves weak here, an adapted design may be justified, but preserve core indicator definitions. Note that two selected centres do not represent Cabo Verde as a whole; a claim about the entire country would require a wider sampling strategy.
Adapt questionnaire design for each survey mode
Different technologies introduce different respondent burdens. A detailed roster may work with an in-person interviewer but be exhausting on a phone. A large grid may look efficient on a desktop yet become nearly unusable on a small smartphone. Break complex tasks into manageable questions, preserve definitions across versions and test the actual devices or connection speeds respondents will use. If mode-specific skips or response formats change the construct being measured, document the decision and avoid careless comparison. Questionnaire harmonisation is a research task, not only a programming task.
Test the actual languages respondents use
Interviewers and respondents may prefer different languages across the same city. Plan local screening, consent and questionnaire testing in Portuguese and Cape Verdean Creole varieties, choosing versions based on the actual target group rather than a single presumed national language. CATI needs phrases that are easy to understand by voice and not overly long. CAWI needs instructions that remain clear without an interviewer. CAPI can support spoken clarification, but staff must not explain questions inconsistently. A short glossary, cognitive pilot and version-control register help maintain concept equivalence across languages and modes.
Plan access, travel and connectivity around local conditions
For this country, a practical design consideration is that inter-island travel and language variety affect recruitment and supervision. Evaluate whether this affects road access for CAPI, call completion for CATI, or digital coverage and completion for CAWI. Conduct a reconnaissance and pilot in each selected centre. Estimate realistic interview duration, interviewer workloads, callback needs, connectivity and secure data transfer rather than applying an unchanged budget from another country. If teams change modes mid-project, document why and test whether the change affects the measured indicators.
Know when mixing modes improves coverage
A mixed-mode design can be sensible if the modes cover complementary groups by design. For example, CAPI might reach selected households lacking reliable numbers, while CATI covers an existing beneficiary list; CAWI might be reserved for digitally active professionals. Do not recruit convenient respondents from all three channels and call the total nationally representative. Agree how invitations will be tracked to prevent duplicates, which questions may be mode-sensitive, and whether final results will be shown separately or weighted into a defined combined population. The reasons for mode allocation should appear in the methods section before results are interpreted.
Apply mode-specific data quality checks
Technology can reduce data-entry mistakes yet leave substantial research error. CAPI interviews may be genuine but sampled conveniently. CATI respondents may be valid but systematically drawn from numbers that answer quickly. CAWI participants may be real people with duplicate links or low attention. Establish mode-specific checks for authenticity, eligibility, consent and completeness. Use supervised observations, callbacks or other permitted verification where appropriate. Report both achieved sample size and data-quality limitations; a clean-looking spreadsheet alone is not a quality certificate.
Treat consent and privacy as part of research design
Privacy safeguards need to be built into the interview workflow. Use the least identifying information sufficient for sampling and follow-up, limit recording and location permissions, and encrypt or otherwise protect transfer and storage appropriately. Provide versions of consent notices respondents can actually understand. Phone calls and household visits may not be private in crowded settings, while self-completed web forms may be viewed on shared devices. Sensitive questions may require different placement, modes or referral procedures. The method should reduce harm, not merely maximise completes.
Analyse mode effects and report coverage limits
Once data arrive, keep mode and recruitment information in the dataset. Examine completion patterns, item nonresponse and demographic composition separately for CAPI, CATI and CAWI. A mode difference may reflect sample composition, question presentation or both. Do not treat every difference as a finding about respondent attitudes. Use weights only where their derivation is credible and explain any residual coverage gaps. A transparent report tells readers how each group was reached, what estimates represent and where interpretation should remain cautious.
An illustrative survey decision for Cabo Verde
Imagine a research organisation assessing Cabo Verde residents’ experience of health or education services. One component may require direct observation of a facility, which favours CAPI; another may involve checking in with beneficiaries already enrolled on a verified contact list, which can favour CATI. A third component may solicit structured feedback from employees or registered online users, which may fit CAWI. The question is not which technology wins overall, but which population and evidence requirement each technology can legitimately serve. For Praia and Mindelo, set different logistics assumptions while applying the same rules for respondent eligibility and data quality.
A method-selection decision for Cabo Verde should explicitly compare: population coverage; sample-frame defensibility; language and questionnaire fit; respondent privacy; requirements for direct observation; connectivity and travel constraints; consent and data protection; interviewer verification; nonresponse; and cost per valid, usable interview. A simple choice table can rank CAPI, CATI and CAWI against the particular study, rather than using a universal hierarchy. A cheap method that systematically misses core respondents is usually a poor value, while an expensive method with no extra evidence benefit may also be hard to justify.
What a credible survey report should contain
The study protocol should specify sampling units, city boundaries, contact or visit schedules, translated questionnaires, mode-specific recruitment procedures, quality checks, data storage and the rules for excluding or replacing cases. Reporting should provide separate denominator and nonresponse information for Praia and Mindelo when they are compared, with a clear limitation on inference beyond those populations. Good survey research gives programme managers and business leaders evidence they can use, plus enough operational detail to understand its strengths and gaps. It does not disguise coverage problems behind a high response count.
How Surveysphere Africa can support
Surveysphere Africa supports the design and delivery of CAPI, CATI, CAWI and carefully planned mixed-mode studies. For projects in Cabo Verde, including Praia and Mindelo, the team can help define a credible sample, localise instruments, supervise fieldwork, verify data quality and explain which populations the evidence represents. The best method is the one that reaches the intended respondents and yields defensible decisions.
Related guidance
For the continent-wide view, read our guide to CAPI, CATI and CAWI.
Our services for research in Cabo Verde
We run research across African markets. Start with these services for work in Cabo Verde:
- Outsourced fieldwork in Cabo Verde: CAPI, CATI and CAWI data collection with live quality control.
- Market and consumer research in Cabo Verde: Market-entry, consumer and retail research.
We also offer: Monitoring, evaluation and learning, Social and development research, Public health research, Policy, economic and institutional research, Data analytics and insights visualisation.
