Designing Questionnaire Studies for Veterinary Research

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• Questionnaire studies in veterinary research are measurement instruments requiring rigorous psychometric evaluation, including content, construct, and criterion validity, alongside test-retest and internal consistency reliability (e.g., Cronbach's alpha ≥ 0.70 for group comparisons).
• Operational definitions of constructs (e.g., pain, quality of life) must precede item generation, with closed-ended items and validated response scales (e.g., Likert, visual analogue) preferred over open-ended items for final instruments.
• The "proxy problem" in veterinary research, where owners interpret animal signs, necessitates explicit control for biases like social desirability, recall bias, and non-response bias through careful item wording, pilot testing, and sampling strategies.
• Probability sampling is ideal for generalizability, but when convenience samples are used, systematic differences between responders and non-responders must be assessed and reported to mitigate bias.
• Pretesting via cognitive interviews and small-scale field trials is crucial to identify comprehension issues and refine items before full deployment, ensuring the instrument measures what it intends to measure across the target population.
• Reporting adherence to EQUATOR Network guidelines (e.g., STROBE for observational studies) is essential for transparency and reproducibility, detailing sampling frames, validation results, and bias mitigation strategies.

Questionnaire studies are a mainstay of veterinary research, yet their design is frequently treated as an afterthought. A questionnaire is a measurement instrument. Like any instrument, it can be calibrated, validated, and assessed for reliability, or it can produce data that are precise but wrong. This article provides a procedural framework for designing, validating, and administering questionnaires in veterinary research, with emphasis on sampling strategy, bias control, and psychometric evaluation. It serves veterinary researchers, graduate students, and clinicians undertaking practice-based research, and it addresses the question of how to construct an instrument that yields defensible answers to a defined clinical or epidemiological question.

The scope covers cross-species applications, from owner-reported outcome measures in companion animals to husbandry and disease surveillance questionnaires in production species. The article assumes familiarity with basic epidemiological concepts and clinical terminology. Qualitative interview methods are excluded, the focus is on structured and semi-structured instruments administered to owners, farmers, or veterinary professionals. The principles described here apply equally to a single-center clinical study and a multinational surveillance program.

At a Glance

The Measurement Problem in Veterinary Questionnaires

Veterinary questionnaires occupy a peculiar position in the research hierarchy. They are observational tools that rely on proxy reporting. The owner or farmer observes the animal, interprets its behavior or clinical signs, and translates that interpretation into a response on a scale. Each step introduces error. The animal's behavior varies with context. The observer's interpretation varies with experience, expectations, and attachment. The response scale imposes its own structure on the observation.

This proxy problem distinguishes veterinary questionnaire research from human survey research. A human patient can confirm a symptom. An owner can only report what they have seen, and their report is filtered through their relationship with the animal. Studies of human health questionnaires have shown that instrument content varies substantially across tools measuring the same construct, and that methodological quality of validation studies is often only fair when assessed against the COSMIN standards. The same caution applies to veterinary instruments. A questionnaire that asks an owner to rate their dog's pain on a numerical scale assumes that the owner can distinguish pain from anxiety, discomfort, or attention-seeking behavior. That assumption must be tested, not presumed.

The consequence is that questionnaire design in veterinary research is fundamentally a psychometric exercise. The instrument must be treated as a test of a latent construct, whether that construct is pain, quality of life, feeding behavior, or disease prevalence. The researcher must demonstrate that the instrument measures what it claims to measure, that it does so consistently, and that its scores can be interpreted meaningfully in the target population.

Defining the Construct and the Research Question

The research question determines every subsequent design decision. A question about the prevalence of a clinical sign requires a different instrument than a question about the severity of that sign, and both differ from a question about the impact of the sign on the owner's quality of life. The construct must be defined operationally before any items are written.

Operational definition means specifying what observations, behaviors, or clinical findings will count as evidence of the construct. For example, if the construct is postoperative pain in cats, the operational definition might include specific behaviors such as reduced grooming, altered posture, decreased appetite, and resistance to handling. Each behavior must be observable and describable in terms that an owner can recognize. The definition should be grounded in the relevant clinical literature and, where possible, aligned with established instruments in the field.

The research question should also specify the population, the setting, and the intended use of the results. A questionnaire designed for a clinical trial of an analgesic will have different psychometric requirements than a questionnaire designed for a national survey of feeding practices. The former needs sensitivity to change over time. The latter needs stability and comparability across populations. These requirements should be stated explicitly in the study protocol before item generation begins.

Item Generation and Response Formats

Items are the building blocks of the instrument. Each item should map directly to one element of the operational definition. Redundancy is acceptable at this stage, items that are poorly worded or ambiguous can be removed during pilot testing. The goal is to generate a pool of items that covers the full content domain of the construct.

Closed-ended items are preferred for most veterinary applications. They are easier to administer, score, and analyze, and they reduce the burden on respondents. The response format must be matched to the item content. A Likert scale with five or seven points is appropriate for agreement or frequency items. A visual analogue scale may be preferable for subjective ratings such as pain intensity. A categorical format with mutually exclusive options is appropriate for factual items such as the presence or absence of a clinical sign.

Response scales require careful attention to anchoring. A five-point Likert scale with anchors ranging from "strongly disagree" to "strongly agree" is balanced and intuitive. A scale that omits a neutral midpoint forces respondents to take a position, which may be appropriate for some constructs but not others. The number of response options affects reliability and discrimination. Too few options lose information. Too many options exceed the respondent's ability to discriminate. Five to seven options are generally adequate for most constructs.

Open-ended items should be reserved for pilot work and for capturing information that cannot be anticipated. They are valuable in the item generation phase, where they can reveal dimensions of the construct that the researcher did not consider. They are problematic in the final instrument because they are time-consuming to code and analyze, and because respondents may provide incomplete or ambiguous answers.

Validation and Reliability Testing

Validation is the process of accumulating evidence that the instrument measures what it claims to measure. It is not a single test but a body of evidence gathered across multiple studies and populations. The COSMIN framework, developed for human health measurement instruments, provides a structured approach to evaluating measurement properties and is directly applicable to veterinary instruments.

Content validity is established during item generation. It requires evidence that the items adequately sample the content domain of the construct. Expert review by veterinarians with relevant clinical experience is the standard method. Each expert should rate each item for relevance, clarity, and comprehensiveness. Items that are consistently rated as irrelevant or unclear should be revised or removed.

Construct validity is assessed by examining the relationship between the instrument and other measures. Convergent validity is demonstrated when the instrument correlates with measures of related constructs. Discriminant validity is demonstrated when the instrument does not correlate with measures of unrelated constructs. Known-groups validity is demonstrated when the instrument distinguishes between groups that are expected to differ on the construct, such as animals with and without a diagnosed condition.

Criterion validity compares the instrument against a gold standard. In veterinary medicine, a true gold standard is often unavailable. The comparison may be against a clinical examination, a diagnostic test, or an established instrument. The choice of criterion must be justified in the study protocol.

Reliability refers to the consistency of the instrument. Test-retest reliability is assessed by administering the instrument to the same respondents on two occasions separated by a period long enough to avoid recall but short enough to avoid genuine change. Internal consistency is assessed using Cronbach's alpha or similar statistics, which measure the extent to which items within a scale correlate with each other. A minimum alpha of 0.70 is commonly cited for group comparisons, with higher values required for individual-level decisions. These thresholds should be attributed to the psychometric literature instead of asserted as universal rules.

Sampling and Bias in Questionnaire Studies

The sampling strategy determines the generalizability of the results. A convenience sample of patients presenting to a single referral hospital cannot represent the general population of animals with a condition. Probability sampling, where every member of the target population has a known probability of selection, is the gold standard. In practice, veterinary researchers often rely on convenience samples, and the limitations must be acknowledged explicitly.

Non-response bias is a particular concern in owner questionnaires. Owners who respond may differ systematically from those who do not. They may have stronger opinions, more time, or different relationships with their animals. The direction and magnitude of this bias can be assessed by comparing respondents with non-respondents on available variables, such as age, sex, or geographic location.

Recall bias affects any questionnaire that asks about past events. Owners may forget episodes of disease, underestimate or overestimate the frequency of behaviors, or reconstruct events in ways that are consistent with their current beliefs. The recall period should be as short as the research question allows, and the instrument should use memory aids such as specific time anchors or calendars.

Social desirability bias is the tendency of respondents to present themselves in a favourable light. Owners may underreport behaviors they consider shameful, such as feeding table scraps or missing preventive care appointments. The instrument can reduce this bias by using neutral wording, assuring confidentiality, and avoiding judgmental language. The residual risk should be discussed in the limitations section of any report.

Reporting Standards

Questionnaire studies should be reported according to the relevant EQUATOR Network guidelines. The STROBE statement applies to observational studies, and the CONSORT statement applies to randomised trials. The ARRIVE guidelines provide the reporting standard for animal research and should be consulted when the questionnaire is part of an interventional study. These reporting standards specify the minimum information required for transparent and reproducible research, and adherence improves the usability of the findings for systematic review and meta-analysis.

Pretesting and Cognitive Interviewing

Pretesting is the first opportunity to observe how respondents actually interpret the instrument. Cognitive interviewing, in which a respondent completes the questionnaire while thinking aloud, reveals mismatches between item intent and respondent comprehension. Ask the respondent to paraphrase each question in their own words, then compare that paraphrase with the intended meaning. Discrepancies identify ambiguous wording, unfamiliar terminology, or items that presuppose knowledge the respondent does not have.

Recruit pretest participants who match the target population in the characteriztics most likely to affect interpretation. For an owner questionnaire about chronic pain, pretest with owners of animals at various disease stages, also with colleagues or students. Colleagues will infer intent from context, owners will not. Conduct at least two rounds of cognitive interviewing, revising items between rounds, until no new comprehension problems emerge.

Following cognitive interviewing, administer the revised instrument to a small pilot sample, typically 30 to 50 respondents, to estimate completion time, item nonresponse rates, and floor or ceiling effects. Items that a substantial proportion of respondents leave blank are either confusing, intrusive, or irrelevant to that subgroup. Items with near-universal endorsement or near-universal rejection contribute little variance and may not discriminate between respondents. The pilot sample also provides preliminary data for assessing internal consistency, although formal reliability testing requires a larger sample.

Administration Mode and Respondent Burden

The mode of administration changes the data the instrument can capture. Self-administered online questionnaires allow branching logic, forced responses, and automated skip patterns, but they exclude respondents without reliable internet access. Telephone administration permits clarification but introduces interviewer effects and limits the use of visual aids such as pain scales or body condition diagrams. Postal questionnaires reach populations without digital access but suffer from lower response rates and longer data collection windows. Clinic-based paper administration captures a captive audience but may bias the sample toward frequent attenders.

Respondent burden is a function of length, cognitive demand, and emotional load. A questionnaire that takes longer than 15 minutes to complete will lose respondents, particularly those with competing demands such as livestock producers during calving season or owners managing a terminally ill pet. Sensitive topics, including euthanasia decisions, financial constraints, or noncompliance with preventive care, require careful phrasing and explicit reassurance about confidentiality. Offer a "prefer not to answer" option for sensitive items instead of forcing a response.

The species and production system change the practical constraints. Dairy producers may complete a lengthy management survey during the winter housing period but not during the grazing season. Companion animal owners are more likely to complete a questionnaire in the waiting room than to follow a mailed request. Wildlife researchers may need to rely on hunter or trapper surveys with short recall periods because the target event is rare and seasonal. Match the administration mode to the population's access patterns, not to the researcher's convenience.

Response Rates and Nonresponse Bias

A low response rate threatens external validity regardless of sample size. The literature on human health surveys, including the food frequency questionnaire validation work in the EPIC-NL cohort, demonstrates that nonresponders differ systematically from responders on health-related behaviors and outcomes. The same principle applies to veterinary questionnaires. Owners who respond to a survey about vaccination practices are likely to hold stronger opinions about vaccination than those who do not respond. Producers who complete a biosecurity questionnaire may manage higher-health herds than those who ignore it.

Report the response rate as the number of completed questionnaires divided by the number of eligible respondents contacted, with the denominator adjusted for undeliverable addresses and ineligible contacts. Compare responders with nonresponders on any variables known for both groups, such as species, breed, age, or geographic region. If the comparison shows meaningful differences, state the direction of the likely bias and its implications for the study conclusions. Do not assume that a high response rate eliminates bias, even a 70 percent response rate can produce distorted estimates if the missing 30 percent differ systematically.

Strategies to improve response rates include prenotification, follow-up reminders, incentives, and keeping the instrument short. Prenotification by postcard or email before the questionnaire arrives increases response in most settings. Two follow-up contacts, the first a reminder and the second a replacement questionnaire, recover a substantial proportion of potential responders. Incentives need not be large, small tokens of appreciation are often sufficient. The choice of strategy depends on the population and the budget, and the effect of each strategy should be reported so readers can judge the risk of bias.

Data Management and Documentation

Plan the data management protocol before data collection begins. Each questionnaire should carry a unique identifier that links to the sampling frame but not to personally identifying information. If the study requires follow-up, maintain a separate linkage file with restricted access. Double entry of a random subset of paper questionnaires quantifies data entry error rates. Online platforms export data directly, but they also produce incomplete or duplicate submissions that must be identified and resolved.

Missing data require a prespecified handling strategy. Distinguish between item nonresponse, where the respondent skips a single question, and unit nonresponse, where the respondent returns nothing. For item nonresponse, determine whether the missingness is random or related to the construct being measured. An owner who skips a question about household income may do so randomly, but an owner who skips a question about the animal's appetite may be avoiding an uncomfortable admission. The distinction changes the appropriate imputation method and the interpretation of results.

Document every version of the questionnaire, including the date of each revision and the reason for the change. This audit trail is essential for reproducibility and for interpreting differences between pilot and final data. The reporting standards for animal research emphasize transparency about methods and materials, and questionnaire studies are no exception. The EQUATOR Network maintains a library of reporting guidelines that includes checklists for survey research, consult these before submission.

Checklist for Questionnaire Development

The following checklist consolidates the steps described in this article and the preceding sections. Use it as a working document during study planning and revision.

The checklist is not a substitute for judgment. A questionnaire that passes every technical check can still fail if the construct was poorly defined at the outset. Conversely, a questionnaire with minor psychometric limitations may be fit for purpose if the study question is descriptive and the sample is representative. Match the rigour of the validation process to the intended use of the data. An instrument used to screen individual animals for a clinical trial requires stronger psychometric evidence than an instrument used to describe population-level trends.

Failure Modes in Questionnaire Studies

Questionnaire research fails in predictable patterns, and most failures are detectable before data collection ends if the investigator monitors for them. The most consequential failure is construct drift, in which the instrument measures something other than the intended construct despite acceptable psychometric indices. This occurs when item generation was not anchored to a defined theoretical framework. Detect it by re-reading each item against the construct definition and asking whether a respondent could answer affirmatively for reasons unrelated to the construct. A second common failure is ceiling or floor effects, where responses cluster at the scale extremes. These are identified during pretesting by examining response distributions, if more than 20% of pretest respondents select the extreme category, the item lacks discrimination and should be revised.

Social desirability bias distorts owner-reported outcomes, particularly for adherence, diet, and husbandry practices. Owners under-report behaviors they perceive as negligent and over-report those they perceive as diligent. Detection relies on embedded validity items or comparison with objective measures where available. A third failure mode is recall decay, which worsens as the recall window lengthens. Food frequency questionnaires and retrospective health histories are vulnerable, the human literature demonstrates that dietary recall instruments produce valid estimates only when the reference period is short and the instrument has been validated against objective intake measures Dietary intake of total, animal, and vegetable protein and. In veterinary studies, the same principle applies to owner recall of clinical signs, medication administration, and dietary composition.

Missing data patterns deserve early scrutiny. If missingness concentrates in specific items, those items are likely confusing, offensive, or irrelevant to a subset of respondents. If missingness concentrates in specific respondents, those respondents may be experiencing burden or literacy barriers. Examine the pattern before analysis, not after.

Common Errors and Corrective Actions

Less experienced investigators frequently confuse reliability with validity. A questionnaire can produce highly reproducible responses that are consistently wrong. Reliability coefficients describe measurement precision, not accuracy. The corrective action is to establish criterion validity against an objective reference standard whenever one exists, and construct validity through convergent and discriminant testing when it does not.

A second error is over-sampling for convenience. Clinic-based convenience samples are efficient but systematically exclude owners who do not present their animals for care, which biases prevalence estimates and association measures. The corrective action is to document the sampling frame explicitly and compare respondent characteriztics with known population parameters where available.

A third error is treating the questionnaire as a measurement instrument when it is actually a screening tool. Screening tools tolerate higher false-positive rates and require confirmatory testing, measurement instruments require stronger psychometric properties. The distinction matters for interpretation. The human quality-of-life literature illustrates this problem: instruments developed for screening are frequently repurposed for outcome measurement without revalidation, and systematic reviews using the COSMIN framework consistently rate the methodological quality of such validation studies as only fair Evaluation of Quality of Life instruments for use in. Veterinary researchers should apply the same scrutiny to instruments adapted from human medicine or from other species.

Limitations of Current Evidence

The veterinary questionnaire literature lags human research in several respects. Species-specific validation studies are scarce, and instruments are frequently adapted across species without formal cross-validation. Owner-reported outcomes are treated as proxies for animal welfare or clinical status, but the relationship between owner perception and objective animal measures is often unexamined. The human literature shows that questionnaire measures of complex outcomes such as sleep disturbance or dietary intake correlate only modestly with objective measures Prenatal mood disturbance predicts sleep problems in infancy and, and veterinary analogues likely show similar or weaker correlations.

Expert opinion still differs on the minimum validation standard for a published questionnaire. Some journals accept instruments with face validity and internal consistency alone, others require test-retest reliability, construct validity, and responsiveness to change. The COSMIN framework provides a structured approach to evaluating measurement properties, but its application in veterinary medicine remains inconsistent. Reporting standards for questionnaire studies are less developed than those for clinical trials, although the EQUATOR Network provides a library of reporting guidelines that includes relevant options for observational and survey research EQUATOR Network Reporting Guidelines.

Escalation and Referral

Most questionnaire design problems are resolved within the research team, but some circumstances warrant external consultation. If validation testing reveals poor psychometric properties and the instrument is central to the study aims, consult a biostatistician or psychometrician before modifying the instrument. If the questionnaire will be used across multiple sites or countries, consult a translation and cross-cultural adaptation specialist. If the study involves regulated species, notifiable diseases, or international data sharing, consult the relevant standards before data collection begins. The World Organization for Animal Health terrestrial code addresses surveillance and reporting obligations that may affect questionnaire content and data handling WOAH Terrestrial Animal Health Code. Institutional review boards or animal ethics committees can advise on owner consent, data protection, and the distinction between research and quality improvement activities. Regulatory reporting is required when questionnaire responses reveal notifiable disease, suspected animal cruelty, or public health risks, the responsible course is to report through the appropriate jurisdictional channel and document the action.

Frequently Asked Questions

How Much Does a Veterinary Questionnaire Study Cost, and Where Should Resources Be Prioritized?

Costs scale with sample size, administration mode, and validation depth. Paper surveys incur printing and postage, while online platforms charge per response above free tiers. Cognitive pretesting with 8 to 12 respondents costs little but prevents expensive rework. Validation studies require larger samples and statistical consultation. Prioritize funding for pretesting, incentive payments to raise response rates, and statistical support for reliability testing. If resources are constrained, reduce sample size before cutting validation steps. A shorter instrument with documented reliability outperforms a longer one with unknown measurement properties. The EQUATOR Network reporting guidelines can help you identify which validation elements reviewers will expect.

What Can I Do When the Ideal Measurement Instrument Is Not Available for My Species?

Adapt a validated instrument from a related species or from human medicine, then revalidate the adapted version. Item wording must change to match the target species and owner perspective. For example, human quality of life instruments assess domains that may not transfer directly to animals, so content validity must be re-established through expert review and owner interviews. The systematic review of quality of life instruments demonstrates how heterogeneous instrument content can be across populations. Report the adaptation process explicitly, including which items were modified, added, or deleted. A partially validated instrument with documented limitations is preferable to an unvalidated instrument created without pretesting.

How Do Questionnaire Design Principles Differ for Production Animals Versus Companion Animals?

The respondent changes the design. For companion animals, the owner reports on a single animal with strong emotional investment. For production animals, the respondent may be a farm manager reporting on groups, and recall accuracy for individual animals is lower. Herd-level questionnaires must define the unit of analysis clearly, whether that is the animal, the pen, or the herd. Production settings also introduce seasonal and management system variation that affects item wording. Welfare and treatment questions may carry commercial sensitivity, so anonymity protections need explicit description. The WOAH terrestrial animal health standards provide context for surveillance-related items that may need to align with international definitions.

What Records Must I Keep During Questionnaire Development and Administration?

Keep every version of the instrument with dates and revision notes. Document the source of each item, whether adapted from published work, generated from interviews, or derived from clinical experience. Retain pretesting transcripts or notes, cognitive interview findings, and the rationale for item changes. Record the sampling frame, recruitment dates, response rates, and any incentives offered. Store raw data in a versioned, read-only format with a separate codebook defining variable names, value labels, and skip patterns. The ARRIVE guidelines for reporting animal research specify minimum information for transparency, and the same logic applies to questionnaire studies. These records support reproducibility and allow reviewers to assess bias risk.

How Should I Explain Questionnaire Findings to a Client or Referring Veterinarian?

Present results as group-level associations, not predictions for an individual patient. State the confidence interval and the study population clearly. For example, a finding that prenatal stress predicts later sleep problems in children, as shown in the ALSPAC cohort study, does not mean one anxious owner will produce a poor sleeper. Explain that questionnaires measure reported behavior, which may differ from observed behavior. Offer the original instrument or a summary of its items so the client can see exactly what was asked. Avoid causal language unless the design supports it. If the questionnaire identified a modifiable factor, frame the recommendation as a trial of change with a defined follow-up period.

When Should I Abandon a Questionnaire Study and Choose a Different Design?

Abandon the questionnaire approach when the construct cannot be defined precisely enough to generate items, when the target population cannot be sampled without prohibitive bias, or when respondents cannot provide accurate answers. For example, asking owners to recall exact medication doses over the past year will produce unreliable data. Consider direct measurement, medical record review, or observational methods instead. If response rates from a pilot fall below 40 percent, nonresponse bias will likely undermine generalizability. The EPIC-NL dietary protein study used a validated food frequency questionnaire, illustrating that even established instruments require population-specific validation. A failed pilot that documents why the instrument failed is more useful than a full study built on an invalid measure.

Related Clinical & Scientific Guides

• Conducting Systematic Reviews of Veterinary Diagnostic Test Accuracy
• Bias in Veterinary Research: Types, Sources, and Mitigation
• Cluster Randomized Trials in Veterinary Research: Design and Analysis

References and Further Reading

• Evaluation of Quality of Life instruments for use in COPD care and research: a systematic review.. 2013.
• Dietary intake of total, animal, and vegetable protein and risk of type 2 diabetes in the European Prospective Investigation into Cancer and Nutrition (EPIC)-NL study.. 2010.
• Improvements in bladder, bowel and sexual outcomes following task-specific locomotor training in human spinal cord injury.. 2018.
• A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Study of Osteoporotic Fractures Research Group.. 2001.
• Prenatal mood disturbance predicts sleep problems in infancy and toddlerhood.. 2007.
• Effects of mothers' prenatal psychiatric status and postnatal caregiving on infant biobehavioral regulation: can prenatal programming be modified?. 2008.
• ARRIVE Guidelines 2.0 for Reporting Animal Research. PLOS Biology, 2020.
• EQUATOR Network Reporting Guidelines. EQUATOR Network.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.

Related Articles

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• Cohort Studies in Veterinary Research: Design and Interpretation
• How to Write a Research Protocol for Veterinary Studies
• Designing Crossover Trials for Veterinary Therapeutics
• Designing Dose-Response Studies in Veterinary Pharmacology

This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.