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Why the right survey method depends on the target population

Before a research agency starts fieldwork in Mozambique, it should decide whether the target population can be reached reliably in person, over the telephone or online. CAPI, CATI and CAWI each provide strengths and distortions. The conditions in Maputo, known in this study context as a southern capital economy, may differ from those in Beira, a central port and logistics city. Designing two city-specific recruitment plans can expose those differences while preserving one consistent research framework.

Design begins with the sample frame. Identify whether eligible respondents can be drawn from mapped dwellings, administrative registers, client records, phone-number frames or authenticated online databases. Each option creates a different set of coverage and nonresponse risks. Research managers should specify the claims they intend to make: city-level description, programme participant feedback or population-representative estimates. The mode must help meet those claims. Changing the interview channel does not rescue a weak frame, and a huge convenience sample remains a convenience sample.

CAPI: when in-person digital interviewing is strongest

Face-to-face digital surveys provide an advantage when sampled units are places rather than contact details. A CAPI team can verify a school, shop, water point, household or health facility in its setting. Interviewers can clarify wording without altering the question and can present consistent showcards if the protocol requires them. That strength comes with practical obligations: listing accuracy, safe transport, translations, device charging and supervisor observations. CAPI should not automatically be treated as nationally representative; the probability of selection still comes from the sample design.

CATI: when interviewer-led telephone surveys fit

CATI reduces travel and can make repeat-contact studies easier when a legitimate phone sampling frame exists. Supervisors can review calling patterns and interviewer performance, and a brief questionnaire may be completed without a site visit. The method is weakest when phone access, privacy or connectivity is uneven. Respondents may share devices, be unable to talk safely or hesitate to trust an unknown caller. Screening, callbacks, translated introductions and a careful nonresponse plan matter as much as the software. Telephone data cannot verify the condition of a physical site without independent evidence.

CAWI: when self-completed online surveys are credible

CAWI can collect rapid feedback from people who are genuinely online, but it needs a credible respondent source. Invitations through an existing customer list answer a different question from open recruitment through advertising. Monitor completion by device type and key demographic group, test visual concepts across common screen sizes and set rules for suspiciously fast interviews. Self-completion may improve privacy for some sensitive questions while increasing misunderstanding for complex ones. The method should be chosen because it fits the study population, not because online questionnaires are easy to distribute.

Use the administrative research geography of Mozambique

A location frame in Mozambique should use the relevant geographic structures, such as provinces, districts and administrative posts, 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.

Build a defensible sample before selecting devices

Choose the frame and recruitment method together. Area-based household sampling, a verified programme register, an updated customer database and a validated online panel each support different estimates. Define nonresponse and substitution rules before fieldwork, and make sample sizes large enough for planned city or demographic comparisons. Combining modes creates an additional issue: a respondent may receive both phone and web invitations or give different answers by mode. Build deduplication and mode monitoring into the protocol rather than discovering these problems after data collection.

Applying CAPI, CATI and CAWI in Maputo

In Maputo, the local research environment includes a southern capital economy. 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 Beira

In Beira, the team should independently assess who can be recruited and how, taking account of its character as a central port and logistics city. 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 Maputo proves weak here, an adapted design may be justified, but preserve core indicator definitions. Note that two selected centres do not represent Mozambique 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, Changana, Sena and other locally relevant languages, 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 cyclone and flood exposure can affect field calendars and comparability. 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

A useful control room turns warnings into action. Unusually rapid CAPI completes should trigger a case review, not pressure on interviewers to be slower. CATI call records should reveal unproductive attempts and concentration in particular contact times. CAWI reports should show drop-off, device compatibility and suspicious repeats. In each case, a supervisor should be responsible for investigating and documenting the outcome. Feedback to the field team must correct processes while avoiding shortcuts that distort sample selection or respondent autonomy.

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

Preserve a single harmonised coding structure while retaining whether each interview came from a visit, call or web form. Assess differences in response patterns and completion quality before estimating overall indicators. If the modes recruited distinct populations by design, report segment-level outcomes rather than forcing a combined national statistic. Document the inference limitations clearly and provide actionable conclusions tied to the actual field evidence. Credible research explains not only what respondents said but how they entered the study.

An illustrative survey decision for Mozambique

Imagine a research organisation assessing Mozambique 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 Maputo and Beira, set different logistics assumptions while applying the same rules for respondent eligibility and data quality.

A method-selection decision for Mozambique 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 Maputo and Beira 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 Mozambique, including Maputo and Beira, 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.

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