# Today, last week or usually: the question changes the answer

Draft • Research checked 4 October 2026 • AI-assisted DomDNA editorial content. No independent clinical review or publication is claimed. General education, not individual medical advice.

“How tired are you?” and “How tired were you over the past seven days?” look similar. They do not necessarily ask for the same information.

One asks about a current state. The other requires a person to recall a period and decide how to summarise it. A questionnaire adds rules to that task through its wording, response options and instructions. Those rules are part of the measurement, not decoration around it.

## Read the time window before the score

A recall period tells you what stretch of experience the answer is meant to describe. It might ask for an average, the worst episode, the number of affected days or the present moment. Those requests can yield different answers from the same person without anyone being dishonest.

[FDA's final patient-reported-outcome guidance](https://www.fda.gov/media/77832/download) discusses matching recall periods to the measurement's purpose and the nature of the experience. It also notes problems that can arise when people reconstruct longer periods from memory.

That does not make every longer recall window invalid or every immediate diary superior. The useful window depends on the concept and the intended interpretation. Burden and completeness matter too: a very frequent record is not automatically helpful if it becomes impossible to sustain.

## A hypothetical week with one difficult day

Imagine an invented seven-day diary in which someone feels comfortable on six days and especially tired on one day. On the final day, three questions could produce quite different answers.

“How tired are you now?” asks about that moment. “How many days were you unusually tired this week?” asks for a count. “How severe was your worst tiredness this week?” deliberately directs attention to the extreme experience.

If the difficult day happens immediately before the questionnaire, it may feel particularly memorable. That possibility is worth recognising, but it does not tell us exactly how much the answer was affected.

No scores or clinical interpretation are assigned here. The example simply shows why a changed question can change the object being measured.

## Wording is an empirical question

An [FDA research-project description](https://www.fda.gov/about-fda/evaluating-physical-functioning-using-patient-reported-outcome-measures-how-does-question-form-and) specifically examines question form and recall period in physical-functioning patient reports. It demonstrates that these are research questions worth testing. The public project description is not a completed study result, and this article does not claim that it established one universally best format.

The [agency-authored perspective on patient-reported outcomes](https://pubmed.ncbi.nlm.nih.gov/17995471/) also links instruments to their intended interpretation and context. A measurement developed for one population or claim should not be assumed to retain the same meaning after casual edits.

That matters when a wellness app shortens a questionnaire, changes “past week” to “usually” or replaces response labels. The modified questions may still be useful for personal reflection, but they do not automatically inherit all the original instrument's evidence.

## Different formats can both be useful

A diary can preserve short-term variation. A periodic questionnaire can summarise a broader experience with less daily burden. A conversation can reveal context that neither score captures. These tools need not compete for one universal winner.

Problems arise when results from different formats are treated as interchangeable. If an earlier questionnaire asked about the past month and a later one asks about today, a difference may reflect the question as well as a changed experience.

Also check whether the instructions ask for an average or a worst experience. Averaging daily diary entries will not necessarily recreate a weekly worst-experience score. More data cannot solve a mismatch in what the questions mean.

## One practical next step

Keep the wording and recall window attached to each personal log or research score. If you change the question, mark the date and treat the new series as a changed measurement until you have a reason to compare them directly.

For a simple personal observation, choose wording you can apply consistently and avoid retroactively rewriting it to fit an interesting result. This is a recording habit, not the creation of a validated symptom instrument.

When reading a study, look for the actual question or named instrument rather than relying on the headline label “energy” or “quality of life”. The time window may explain what the finding does and does not cover.

A questionnaire answer is data about an experience under particular instructions. Reading those instructions can be more informative than another decimal place in the score.

For an educational starting point, the [DomDNA lifestyle quiz](https://domdna.com/quiz) records lifestyle answers, not DNA analysis or a clinical diagnosis.