There are five ways to put a questionnaire in front of a human being, and the choice decides your cost, your timeline, and — through mode effects — some of your results. Here is each method with honest trade-offs, what it costs, and how to choose.
By the Wavefield Research team · Published Aug 7, 2026 · Updated Aug 18, 2026
Most articles on this topic muddle two different decisions. The collection method — researchers say mode — is the channel the questionnaire travels through: a browser, a text message, a phone call, a doorstep, an envelope. The sample source is where the people come from: your customer list, a purchased panel, a random-digit dial frame, foot traffic.
The two mix freely — a web survey can be answered by your own customers or by paid panelists, and the results differ far more by that choice than by anything about the browser. This page covers the modes; how respondents are chosen is the subject of quota sampling vs. random sampling.
One study, three delivery channels — the same questionnaire, quotas, and quality flags apply across all of them, so the mode mix is a fielding decision, not three separate surveys.
Five true modes plus the panel, which behaves like a sixth in budget discussions. Every one of them is the right answer for some population and the wrong answer for others — the trade-offs below are the ones that decide real studies.
Best for: most consumer and B2B studies where the audience is reachable by email, text, or a link.
The default mode of modern research: respondents self-complete in a browser, usually on a phone. Fieldwork closes in days, marginal cost per response is near zero with your own list, and every visual question type — grids, rankings, images — works. The weaknesses are coverage (you only reach people who are online and willing) and self-selection on open links; single-use invitation links and quotas are the standard counters.
Best for: audiences that do not live in their inbox — customers, field staff, younger demographics.
An invitation arrives by text with a link to the same web survey. Text messages get read at rates email has not seen in decades, so contact rates are excellent — but the survey must be short and mobile-first, and compliance is non-negotiable: documented consent, immediate STOP opt-outs, and message-rate disclosures. Cost is per message sent, not per complete.
Best for: older populations, election polling traditions, and anyone unreachable online.
A trained interviewer administers the questionnaire by phone. The interviewer can clarify and probe, and telephone frames still cover people the internet misses — but single-digit cooperation rates are now normal, pushing cost per complete into the tens of dollars, and the human on the line measurably inflates socially desirable answers. Question types are limited to what can be read aloud.
Best for: long interviews, product handling, and populations with low connectivity.
The most expensive mode by an order of magnitude, and still the gold standard for interview depth: an hour of attention, physical stimuli, show cards, and high response rates once a door opens. Official statistics and central-location product tests keep it alive. For most commercial studies the cost and weeks-long fieldwork rule it out.
Best for: statutory surveys and populations that distrust or lack digital channels.
A printed questionnaire with a return envelope. Response arrives over weeks, reminder mailings are half the budget, and there is no skip logic, piping, or randomization — the instrument must survive on paper exactly as printed. Response rates of 5–20% with reminders are typical. Manual data entry adds a final error source the digital modes do not have.
Best for: filling general-population quotas fast when you do not own a respondent list.
Strictly a sample source rather than a separate mode: panelists answer the same web survey, but a panel company recruited them and pays them per complete (rough order of magnitude: a few dollars each for general population, far more for specialists). Quality varies enormously — speeders, duplicates, and professional respondents are the known failure modes — so screeners and automatic quality flags are not optional extras here; they are the price of admission.
Order-of-magnitude figures for a general-population study in North America — every project varies, but the relative picture is stable and it is the picture that drives method choice.
| Method | Typical speed | Cost per complete | Response | Where it wins |
|---|---|---|---|---|
| Online (own list or link) | Hours to days | Near zero marginal | 10–30% of a warm list | Speed, cost, question flexibility |
| SMS text-to-web | Hours | Cents per message | Highest read rates; short surveys only | Reaching people who ignore email |
| Online panel | Days | A few dollars per complete | Quota-driven, not rate-driven | General-population reach without a list |
| Telephone (CATI) | Days to weeks | Tens of dollars per complete | Single digits and falling | Offline and older populations |
| Face-to-face (CAPI) | Weeks to months | Highest by far | High once contact is made | Depth, stimuli, low-connectivity areas |
| Postal mail | Weeks to months | Print + postage + reminders | 5–20% with reminder waves | Statutory surveys, digital-averse groups |
Response rates deserve one honesty note: a low rate is not automatically a biased sample, and a high one is not automatically clean — what matters is whether responders differ from non-responders on what you are measuring. Quotas and weighting exist precisely to repair known skews; survey weighting, explained covers how.
The collection method is not a neutral pipe. Decades of methodology research document systematic differences in what people answer depending on how they are asked — and every one of them has burned a real study:
The method decides who can possibly answer before a single question is asked. Telephone frames miss the mobile-only and the never-answer generation; online misses the offline, who skew older and rural; mail misses the mobile. Choose the method from the population, never from convenience — the cheapest mode that actually covers your population is the right one.
People confess more to a screen than to a human. Interviewer modes — phone and face-to-face — reliably inflate church attendance, voting intention, and charitable giving, and deflate drinking, debt, and prejudice. Self-administered modes get more honest answers on anything sensitive. If a tracker switches from CATI to online and the numbers move, the mode moved them.
Visual modes push respondents toward the first options they see; aural modes push toward the last options they heard. The counter online is randomizing option order so position effects cancel out — but nothing cancels the difference between modes, which is why comparing a phone wave to a web wave option-by-option is a methodology error, not a trend.
With no interviewer setting the pace, self-administered respondents speed, straightline grids, and pick the first acceptable answer. The fixes are structural: short questionnaires, grids under seven rows, and automatic quality flags for speeders, straightliners, and failed attention checks — marked for review, not silently deleted, so the audit trail survives.
Work through three questions in order. Coverage first: which modes can physically reach your population? If the answer is only one, the decision is made. Then budget and clock: among the modes that cover, take the cheapest and fastest — for most commercial populations that is online, extended by SMS for people who ignore email. Then consistency: if the study is a tracker, the mode you pick is the mode you keep, because a mid-tracker mode switch moves numbers all by itself.
Mixed-mode designs — web first, mail or SMS follow-up for non-responders — are legitimate and often the only way to cover a stubborn population. The discipline is to keep the questionnaire identical across modes, record the mode on every response, and compare key measures by mode before pooling anything.
On Wavefield, fielding is online and SMS with your own respondents — shareable links, single-use email invitations, and consent-enforced SMS invitations — with quotas, screeners, and quality flags running automatically across every channel. The questionnaire itself is drafted by the agent from your brief; survey programming, explained covers that side.
Five modes cover practice: online (web) surveys, SMS text-to-web, telephone interviewing (CATI), face-to-face interviewing (CAPI), and postal mail. Online panels are often listed as a sixth, but they are really a sample source — paid respondents answering an online survey. Most commercial research today is online, with SMS as the reach extender and interviewer modes reserved for populations the internet cannot cover.
Online, by a wide margin — with your own contact list or a shareable link, the marginal cost per response is close to zero. SMS adds cents per message. Panel sample costs a few dollars per general-population complete. Telephone interviewing runs tens of dollars per complete, and face-to-face is the most expensive by an order of magnitude. Cheap only counts if the mode covers your population and the data passes quality checks.
A difference in answers caused by the collection method rather than by real opinion. The classic examples: people admit less to human interviewers than to screens (social desirability), visual modes favor the first options shown while aural modes favor the last heard (primacy vs. recency), and unsupervised respondents satisfice more. Mode effects are why trackers keep the same method across waves — changing it mid-tracker moves the numbers even when opinion is unchanged.
Yes — mixed-mode designs are standard practice, typically a web survey with mail or SMS follow-up to reach non-responders. The requirements: keep the questionnaire identical across modes, record which mode each response came from, and check key results by mode before pooling. What you should not do is blend modes silently, or switch a tracker's mode between waves without a bridging plan.
The method delivers the questionnaire — what goes in it is covered in survey question types, with examples, and how many completes you need in the sample size calculator. After fielding: how to analyze survey results
Upload a brief, review the agent's questionnaire, and field through links, email, or SMS — quotas and quality checks included, free to build.
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