Collect data through self-reporting

A questionnaire questionnaire A structured, standardised set of questions that are posed in the same way to survey participants. A questionnaire often includes filter questions and the response to these will influence subsequent questions. Find out more serves both as a means of communication with the respondent and as a tool for gathering information. Its purpose is not merely to ask questions, but to translate a need for information into actionable answers without distorting the observed reality. The design of the questionnaire therefore directly influences measurement error error There are different types of errors in surveys : coverage error (the sampling base does not correspond exactly to the population studied), non-response error (a part of the sample does not wish to answer certain questions), measurement error (the value declared by the individual is incorrect) and sampling error (only a part of the population is observed). The combination of these errors - the total error - is the difference between the survey-estimated value and the (generally unknown) “true value” of the parameter in the population. Find out more and non-response non-response People solicited to participate in a statistical survey do not always respond - in this case they are called non-responses. “Total non-response” cases (when a person contacted for a survey does not respond to any question at all) are distinguished from “partial non-response” cases (when the interviewee responds to some questions, but not others). Find out more .

From the respondent’s perspective, three conditions must be met: they must understand the question question An inquiry posed in the same way to all participants in the same survey, with the goal of obtaining answers of the same nature. We distinguish closed questions whose responses are chosen from the options provided (scales, yes / no, classification options, etc.), from open-ended questions for which no answer categories are offered. In the latter case, the spontaneous answer of the interviewee is gathered. Find out more , be able to answer it, and be willing to answer it. This threefold requirement is central, because answering a questionnaire involves a complex cognitive process: perceiving the question, understanding the question, searching for the information needed to answer it, evaluating the relevant information, and then converting that information into the expected response format. Any flaw in wording or presentation can disrupt one or more of these steps.

This means that a “good Questionnaire” is not merely one that covers all the desired topics, but one that yields interpretable, comparable, and actionable responses. A questionnaire that is too ambitious, too dense, or too technical may give the illusion of depth, when in reality it could produce inaccurate information.

1. Focus the Questionnaire Questionnaire A structured, standardised set of questions that are posed in the same way to survey participants. A questionnaire often includes filter questions and the response to these will influence subsequent questions. Find out more on the research question question An inquiry posed in the same way to all participants in the same survey, with the goal of obtaining answers of the same nature. We distinguish closed questions whose responses are chosen from the options provided (scales, yes / no, classification options, etc.), from open-ended questions for which no answer categories are offered. In the latter case, the spontaneous answer of the interviewee is gathered. Find out more

Before drafting a Questionnaire, you must define the research question, clarify the information needs, conduct a literature review if necessary, and often carry out a preliminary qualitative phase. This process is essential: A questionnaire is best designed when you know precisely what you are seeking to measure, for what purpose, and for which audience audience The set of listeners, viewers, or TV viewers in which each individual is equally weighted, regardless of their listening/viewing duration or frequency of contact. Find out more .

A best practice is therefore to start with the indicators to be produced, then work backward to the necessary variables, and finally to the questions capable of collecting those variables. This approach helps avoid overly long Questionnaires that include questions unrelated to the objective or of little use to the final analysis. The fundamental principle is relevance: ask only the necessary questions, and only of the people concerned, using well-designed filters. An effective questionnaire is, first and foremost, a focused questionnaire.

2. Formulate simple, precise, and unambiguous questions

The fundamental principles for writing questions are: brevity, neutrality, and one-dimensionality. A question question An inquiry posed in the same way to all participants in the same survey, with the goal of obtaining answers of the same nature. We distinguish closed questions whose responses are chosen from the options provided (scales, yes / no, classification options, etc.), from open-ended questions for which no answer categories are offered. In the latter case, the spontaneous answer of the interviewee is gathered. Find out more should be short, direct, focus on a single idea at a time, and not suggest the answer. “Double-barreled” questions are a classic example of poor questionnaire questionnaire A structured, standardised set of questions that are posed in the same way to survey participants. A questionnaire often includes filter questions and the response to these will influence subsequent questions. Find out more design: for example, asking whether a product is “innovative and reliable” forces the respondent to combine two distinct judgments, making the answer difficult to interpret.

You should also avoid vague or ambiguous terms, industry jargon, negative phrasing or double negatives, as well as vague time frames. It’s better to use numerical or date-based references: “over the past 30 days,” “three times a week,” “since January 2026.” This precision promotes accuracy and comparability.

Neutrality is equally important because it encourages honest responses.

3. Pay Attention to the Order of Questions

A questionnaire questionnaire A structured, standardised set of questions that are posed in the same way to survey participants. A questionnaire often includes filter questions and the response to these will influence subsequent questions. Find out more is more than just a collection of independent items. The order of the questions influences comprehension, the context of interpretation, and sometimes even the content of the responses. The context and order of the questions can alter the observed response distributions. It is best to start with general, simple, and engaging questions, gradually moving toward more specific or sensitive ones.

In practical terms, it is recommended to structure the questionnaire into clear, readable sections: a pitch, a presentation of the objective, an eligibility check, the main questions, and then, if necessary, optional follow-up questions. Eligibility criteria and quotas must appear early enough to avoid unnecessarily engaging respondents outside the target target A subset of the population which we aim to reach with a show or advertising campaign. The target is defined using socio-demographic, equipment, or behavioural characteristics. Find out more audience audience The set of listeners, viewers, or TV viewers in which each individual is equally weighted, regardless of their listening/viewing duration or frequency of contact. Find out more . Consistent sequencing and a smooth flow of the questionnaire help reduce respondent fatigue.

Filters must also be carefully worded.

Eligibility criteria and quotas must appear early enough to avoid unnecessarily engaging respondents outside the target audience. Consistent sequencing and a smooth flow of the questionnaire help reduce respondent They serve not only to route respondents but can also reduce the memory load if they explicitly reiterate elements already mentioned.

4. Choosing the Right Question Question An inquiry posed in the same way to all participants in the same survey, with the goal of obtaining answers of the same nature. We distinguish closed questions whose responses are chosen from the options provided (scales, yes / no, classification options, etc.), from open-ended questions for which no answer categories are offered. In the latter case, the spontaneous answer of the interviewee is gathered. Find out more Format

Open Questions, Closed Questions, Semi-Open Questions, Rating Scales, and Rankings: no single format is “best” in general; it all depends on the intended objective.

Open Questions allow for spontaneity and nuance, which are particularly useful during the exploratory phase. On the other hand, they are more tiring for respondents and make coding and analysis more time-consuming. Closed questions are easier to administer, faster to process, and often more comparable—provided you avoid overly long lists of response options. Semi-open-ended questions are sometimes a good compromise: they ensure reliable measurement while allowing for unexpected responses to emerge.

Rating scales must be used with discretion: one must choose the number of points, decide whether or not to include a Median Median In statistics, the median is the value that splits all the values into two equal parts. Find out more , and, above all, clearly label the response options.

It is sometimes recommended to vary question formats to counter respondent fatigue.

5. Consider the layout as well

Layout is an essential aspect of the Questionnaire Questionnaire A structured, standardised set of questions that are posed in the same way to survey participants. A questionnaire often includes filter questions and the response to these will influence subsequent questions. Find out more . The layout, the proximity between questions and answers, the visual similarity of elements of the same type, the simplicity of the screen or page, and the consistency of the reading direction all contribute to comprehension.

This aspect is fundamental in multimodal or self-administered self-administered A questionnaire that is filled in directly by the interviewee, not by an interviewer. This is most often a postal questionnaire, or, increasingly, one that is available online for certain websites. Find out more questionnaires, but it must not be overlooked in the case of interviewer-administered questionnaires.

For survey survey A statistical method that aims to produce information about a population by interviewing part of the population (sample). This word is generally used to mean a survey conducted on a sample that have been interviewed using a questionnaire or else systematically observed. Find out more practitioners, this means testing not only the wording of the questions but also the visual presentation across all possible mediums (computer, mobile phone, or tablet), as well as the clarity and display display Display Advertising, or Bannering, is the most traditional interactive advertising channel. The advertiser uses pre-set advertising spaces on websites (banner, skyscraper, IMU, leaderboard, etc.) Find out more of instructions, prompts, and intermediate screens. A well-written but poorly displayed Questionnaire remains a vulnerable Questionnaire.