03 · What You Need to Know
How to Modify an Existing Questionnaire Without Undermining Its Measurement Purpose
What Counts as Modifying an Existing Questionnaire?
Questionnaire modification involves changing one or more features of an existing instrument rather than administering it exactly as originally specified.
Changes may concern wording, item content, instructions, response categories, recall periods, administration mode, scoring procedures, or the population for which the instrument is used.
For example, a questionnaire originally designed for classroom instruction might be modified to refer to asynchronous online learning.
Although the modification appears contextual, it may change the experiences respondents consider when answering.
Researchers should therefore distinguish changes that improve comprehension while preserving intended meaning from changes that alter the construct or measurement task.
Why Might Questionnaire Modification Be Necessary?
Existing instruments are developed for particular purposes and populations. Their wording and administration procedures may not be suitable in every setting.
Modification may be justified when an instrument contains context-specific terminology, assumes experiences unavailable to the intended population, or requires an accessible administration format.
For example, a questionnaire about instructor feedback may refer to face-to-face consultations, whereas students in a fully asynchronous program receive feedback through learning management systems.
Replacing the reference to consultations with a suitable description of feedback practices might improve contextual relevance.
However, the researcher must determine whether the revised item still represents the same underlying attribute.
The decision should begin with evaluating the measure's appropriateness for the intended population and context.
What Types of Questionnaire Modifications Are Common?
| Modification |
Illustration |
Potential Measurement Consequence |
| Editorial clarification |
Correcting punctuation or an obvious typographical error |
Usually limited, unless meaning or emphasis changes |
| Contextual wording |
Replacing "classroom" with "online course" |
May change the situations respondents consider |
| Item removal |
Deleting questions considered irrelevant |
May reduce construct coverage or alter scoring |
| Item addition |
Including questions about AI-supported learning |
May expand or change the measured construct |
| Response-format change |
Replacing seven agreement categories with five |
May affect response behavior and score comparability |
| Recall-period change |
Changing "past month" to "past week" |
May change the temporal meaning of the measurement |
| Administration-mode change |
Moving from paper to an online interface |
May introduce presentation or mode effects |
| Translation or cultural adaptation |
Preparing an instrument for another language group |
May change item interpretation or measurement equivalence |
| Scoring modification |
Changing item weights or total-score calculations |
May alter score meaning and relationships with other variables |
These changes do not carry identical risks. Their consequences depend on the instrument, construct, and intended use.
Can You Make Minor Wording Changes Without Revalidation?
Some editorial corrections may have negligible measurement consequences.
For example, correcting a typographical error that does not affect meaning is different from replacing a key conceptual term.
However, the distinction between minor and substantive wording changes cannot always be established from appearance alone.
Changing "I can complete difficult tasks" to "I regularly complete difficult tasks" shifts the item from perceived capability toward reported behavior.
Both statements concern academic tasks, but they ask respondents to make different judgments.
Researchers should evaluate whether the revised wording preserves the intended construct and response process.
When uncertainty remains, a limited cognitive review may be more defensible than assuming equivalence.
Can You Remove Items From an Established Questionnaire?
Items may be removed when there is a defensible reason, such as contextual inapplicability, excessive burden, or evidence that particular content is unsuitable.
However, removing items may change the construct domain, dimensional structure, reliability, and scoring.
For example, deleting several items concerning reflection from a self-regulated learning questionnaire could leave the resulting instrument disproportionately focused on planning.
The shortened version may no longer support the original broad score interpretation.
Researchers should therefore evaluate the content and measurement consequences rather than assuming that fewer questions produce an equivalent instrument.
The specific issue of whether removing questionnaire items creates a new instrument requires attention to the extent and substantive consequences of the deletion.
Can You Add Items to an Existing Questionnaire?
Adding items may be justified when the existing questionnaire omits content essential to the intended research purpose.
However, additional items can change the construct represented by the total score or introduce dimensions not included in the original instrument.
For example, adding questions about students' use of generative AI to an academic self-efficacy questionnaire does not automatically improve its measurement of self-efficacy.
The new items may instead concern technology use, confidence in AI tools, or academic practices.
Researchers should determine whether the additions represent the original construct, a distinct dimension, or a separate variable.
Where additional content is necessary, it may be preferable to administer supplementary items separately rather than incorporate them into the established score.
Can You Change the Response Options?
Changing response categories may affect how respondents express judgments and how scores are interpreted.
For example, replacing a seven-category agreement scale with five categories reduces the number of distinctions available to respondents.
It may also change the meaning of the midpoint or the relationships among item responses.
Even when scores are mathematically rescaled, the modified response process may not be equivalent to the original.
The question of changing questionnaire response options without revalidation should therefore be considered before altering an established format.
Can You Change the Recall Period?
A recall period specifies the time frame respondents should consider when answering.
Changing "during the previous four weeks" to "during the previous seven days" may alter the experiences represented by the response.
Shorter recall periods may reduce some memory demands but may also produce different estimates of behavior or experience.
The direction and magnitude of these effects depend on the phenomenon being measured.
Researchers should therefore avoid assuming that a shorter or more convenient recall period is automatically superior.
Any modification should be justified by the construct, study design, and available measurement evidence.
Can You Change a Paper Questionnaire Into an Online Questionnaire?
Potentially. Moving an instrument to an online interface may improve accessibility, efficiency, or data recording.
However, administration mode can influence item presentation, privacy perceptions, navigation, and response behavior.
For example, a matrix question displayed on one printed page may appear as separate items on a mobile screen.
These differences may alter how respondents interpret or compare the response options.
Researchers should evaluate whether the digital version preserves the intended measurement and whether relevant mode-comparability evidence is available.
The change should not automatically be treated as a purely technical conversion.
When Does Modification Become Instrument Adaptation?
Instrument adaptation generally involves modifying an existing measure so that it is suitable for another population, language, culture, context, or administration condition while attempting to preserve the intended construct.
Modification is a broader term that can describe any change to the instrument.
Not every modification constitutes a formal adaptation, and extensive adaptation may produce an instrument that differs substantially from the original.
For example, replacing a few context-specific expressions may preserve much of the original content. Rewriting most items, changing the dimensions, and introducing a different scoring system may constitute substantial redevelopment.
There is no universally accepted percentage of changed items that determines when adaptation becomes new development.
The distinction should be based on conceptual and measurement consequences rather than a numerical threshold.
Does the Original Instrument's Validity Evidence Still Apply?
Some evidence may remain relevant, particularly when the modification is limited and the intended construct and population are closely comparable.
However, the evidence cannot automatically be transferred without examining the consequences of the change.
For example, an established questionnaire may have strong evidence supporting a three-dimensional structure. Removing items or changing response categories could affect whether that structure remains appropriate.
Similarly, evidence from one language or cultural context may not establish equivalent item interpretation elsewhere.
Validity is associated with particular interpretations and uses of scores, not with the questionnaire's title alone.
The researcher should identify which existing evidence remains applicable and which properties require additional investigation.
What Is the Difference Between Revalidation and Additional Validity Evidence?
The term "revalidation" is commonly used to describe evaluating a modified instrument, but it can suggest that validity is a one-time status that must be renewed.
A more precise approach is to identify the additional evidence required to support the modified instrument's intended score interpretation.
For example, a contextual wording change may primarily require evidence about comprehension and content relevance.
A substantial change to the item set may also require renewed investigation of dimensional structure and reliability.
A modification affecting group comparisons may require evidence about measurement equivalence.
Researchers should match evaluation procedures to the specific risks introduced by the modification rather than automatically repeating every possible statistical test.
What Role Should Experts Play in Questionnaire Modification?
Experts can evaluate whether proposed changes preserve the construct definition, content coverage, and intended measurement purpose.
For example, a subject specialist may determine whether replacing a context-specific activity with another activity preserves the same theoretical attribute.
Measurement specialists may identify problems with revised response categories, scoring rules, or item construction.
However, expert approval alone does not establish that respondents interpret the modified questions as intended.
Expert review should therefore be integrated with other evidence where appropriate.
Why Should the Target Population Review Modified Items?
Modified wording may introduce new interpretations even when the researcher intends to preserve the original meaning.
Members of the target population can help identify unfamiliar terminology, contextual assumptions, and response difficulties.
For example, students in asynchronous courses may interpret "class participation" differently from students attending scheduled classroom sessions.
Appropriate target-population review can identify these differences before the modified questionnaire is used in the main study.
Where the changes are consequential, cognitive interviewing may provide more detailed evidence about how respondents understand and answer the revised items.
Can Statistical Analysis Demonstrate That the Modified Questionnaire Is Equivalent?
Statistical analysis may contribute evidence about the modified instrument's measurement properties, but the appropriate method depends on the question.
For example, factor analysis may evaluate whether the proposed structure remains plausible, while measurement invariance analysis may investigate comparability across groups.
Reliability analysis can provide evidence about score precision under specified conditions.
However, favorable statistical results do not independently establish that modified items retain the intended conceptual meaning.
Similarly, a high correlation between original and modified scores does not necessarily establish numerical interchangeability or equivalent construct coverage.
Statistical evaluation should complement conceptual and response-process evidence.
Can You Modify a Questionnaire Without the Original Author's Permission?
The answer depends on copyright, licensing conditions, contractual terms, and applicable law.
Some instruments are distributed under licenses that permit specified forms of reuse or adaptation. Others require authorization before reproduction, translation, or modification.
Researchers should examine the instrument's official documentation and applicable terms before making changes.
Publication of questionnaire items in a journal article does not automatically mean unrestricted adaptation is permitted.
Likewise, citing the original author does not independently establish permission to reproduce or modify protected material.
Researchers should retain relevant permission records and distinguish legal authorization from methodological appropriateness.
Should You Still Call It the Original Questionnaire After Modification?
The name used should accurately communicate the relationship between the modified version and the original instrument.
For minor changes, it may be appropriate to describe the instrument as an adapted version, provided the modifications are clearly documented.
For substantial redevelopment, retaining the original name without qualification may mislead readers about the instrument's content and supporting evidence.
Researchers should avoid implying that a modified version has identical measurement properties simply because it retains the original title.
Where appropriate, identify the version, modifications, and original source explicitly.
How Should Questionnaire Modifications Be Documented?
Maintain a record of the original and revised wording, the rationale for each change, and the evidence used to evaluate its consequences.
Document changes to item inclusion, response options, recall periods, administration, and scoring.
Where applicable, record permissions and version identifiers.
In the methodology, explain why the modifications were necessary and which measurement properties were examined afterward.
The detailed process of documenting research instrument modifications is especially important when several versions are used across sites or study phases.
When Should You Avoid Modifying an Existing Questionnaire?
Modification may be difficult to justify when the original instrument already adequately represents the construct and the proposed changes provide no substantive advantage.
It may also be risky when extensive changes are required but the research team lacks the resources to evaluate the resulting instrument.
For example, shortening a well-supported questionnaire solely to save a small amount of administration time may not be worthwhile if the changes substantially weaken content coverage.
Researchers should also reconsider modification when the original construct is fundamentally different from the intended attribute.
In such circumstances, selecting another instrument or developing a new measure may be more defensible.
Watch Out
Do not assume that a modified questionnaire remains validated simply because its original version has published reliability and validity evidence. Even apparently modest changes may alter item meaning, response processes, scoring, or construct coverage. Evaluate the consequences rather than relying on the original instrument's reputation.
