Instrument template · PainUpdated September 28, 2026

A VAS pain scale that behaves like the paper line

The visual analogue scale is the simplest pain measure there is, and the easiest to get wrong on a screen. This template uses a 0 to 100 slider with anchors and no preset marker, so participants place their own answer.

  • 0 to 100, no preset value
  • Anchors at both ends
  • Daily or visit-based

Free sandbox · No credit card · 21 CFR Part 11 aligned

Pain today

Evening diary · Day 12

Mark how bad your pain has been over the last 24 hours

No painWorst pain imaginable

Did you take rescue medication today?

NoYes
Marker starts empty, not at 50

VAS pain scale at a glance

  • A line with two anchors, typically "no pain" and "worst pain imaginable". The participant marks a point; the score is the distance from the left end, 0 to 100.
  • Commonly used severity ranges: 0 to 4 no pain, 5 to 44 mild, 45 to 74 moderate, 75 to 100 severe.
  • The recall period is set by your protocol: pain now, average over 24 hours, worst over the last week. State it in the question.
  • On screen, the marker must not start at a preset position, or participants anchor on it. Capture's visual analogue scales have no preset value.
  • The VAS is a generic format, not a licensed instrument. For many trials an 11-point numeric rating scale (0 to 10) is simpler and equally accepted.

The scale

Why the VAS is simple and still easy to get wrong

On paper the VAS is a 100 mm line and a ruler. Its appeal is sensitivity: participants are not forced into categories, so small changes are visible. Its weaknesses are practical. Some participants, especially older people or those with visual or motor difficulties, find it harder to use than a numbered scale, and on paper the measurement step adds a transcription risk.

Moving the VAS onto a screen removes the ruler, but introduces new risks. Screen widths differ, so the score has to be stored as a proportion of the line (0 to 100), not as millimetres on a particular device. And many slider controls start at the midpoint, which quietly biases answers towards 50. The template solves both: scores are stored 0 to 100 and the marker starts empty.

Choosing the recall period and wording

Pain now, average pain over the last 24 hours and worst pain over the last week measure different things. Choose the one that matches your endpoint, put it in the question itself, and use the same wording at every administration. For daily diaries, "over the last 24 hours" completed at the same time each evening is a common choice.

VAS or NRS?

The 11-point numeric rating scale (0 to 10) is easier for many participants, easy to read aloud by phone, and widely used in pain trials. The VAS offers finer resolution. If you have no specific reason to use a VAS, discuss an NRS with your statistician; if you do use a VAS, keep it consistent across the program. The pain diary template uses a numeric scale.

VAS pain · Subject 008-0026

Average pain, last 24 h

46 / 100

Moderate
0-4 No pain5-44 Mild45-74 Moderate75-100 Severe
Week 1 average63
Week 2 average52
Week 3 average46

Daily diaries

Pain changes daily. Collect it daily.

Pain trials usually average daily scores over a week rather than relying on a single visit rating. Capture runs the VAS as a recurring diary with a completion window each evening, reminders that respect quiet hours, and compliance visible on the dashboard, because a weekly average built from three entries is not much of an average.

  • Recurring daily schedule with an evening completion window.
  • Reminders when due, the next day and before the window closes.
  • Rescue medication and sleep interference questions on the same diary.
  • At-risk participants highlighted before compliance drops too far.
Patient diary software
ePRO compliance by site
Site 0194%
Site 0281%
Site 0358%

At-risk participants

03-0073 diary entries missedReminder delivered
03-011Week 4 questionnaire overdueEmail bounced

Any device

Same scale on a phone, a tablet or in clinic

Participants use their own phone in the browser, or a clinic tablet at visits, in portrait or landscape. Controls are touch-sized and the score is stored on the same 0 to 100 scale whatever the screen width.

Clinic tablet · landscape5 of 12

How much pain do you feel right now?

No painWorst pain
BackNext

Try the VAS on your own phone

Build a daily pain diary with a VAS in the sandbox and complete it tonight.

Use the VAS template free

As an endpoint

Using VAS pain scores as a trial endpoint

Pain intensity is the primary endpoint in most analgesic trials, and how it is summarised matters as much as how it is collected. A single rating at a clinic visit is noisy; the mean of daily ratings over a week is far more stable. Most chronic pain trials therefore collect daily scores and analyse the weekly average, with a baseline week before randomisation.

Responder analyses

Alongside mean change, pain trials commonly report the proportion of participants achieving at least a 30% reduction (often described as moderately important) and at least a 50% reduction (substantial), following widely cited consensus recommendations for chronic pain trials. Pre-specify them in the analysis plan.

Rescue medication

If participants may take rescue analgesics, pain scores on those days reflect the rescue drug as well as the study treatment. Ask about rescue medication on the same daily diary, so the analysis can handle it as the estimand requires.

Baseline eligibility

Many protocols require a minimum average baseline pain (for example moderate pain on most days of the baseline week) and a minimum number of completed diary days. Building those rules on data captured in the diary, rather than on a single screening rating, reduces enrolment of participants whose pain is too variable to show a treatment effect.

Before go-live

VAS setup checklist

Anchors and wording fixed

Same anchor text and recall period in every administration.

No preset marker

Participants place the marker themselves; confirm in the preview.

Daily schedule and window

Same time each day, with an evening completion window and reminders.

Rescue medication captured

A yes or no question on the same diary.

Baseline rules written

Minimum baseline pain and minimum diary days before randomisation.

Responder definitions pre-specified

30% and 50% reductions, or your protocol's own thresholds.

FAQ

Questions about this template

Something not covered here? Ask us directly.

How is a VAS pain score calculated?

It is the position of the participant's mark along the line, from 0 at the "no pain" end to 100 at the "worst pain imaginable" end.

What VAS scores mean mild, moderate and severe pain?

Commonly used ranges are 0 to 4 no pain, 5 to 44 mild, 45 to 74 moderate and 75 to 100 severe.

Why should the slider not start in the middle?

A preset position anchors participants towards it. Capture's visual analogue scales have no preset value, so the participant places the marker.

Is the VAS licensed?

No. It is a generic scale format. Specific named instruments that include a VAS may have their own licensing.

VAS or NRS for a pain trial?

Both are widely accepted. The 0 to 10 NRS is easier for many participants; the VAS offers finer resolution. Keep the choice consistent across your program.

Can the VAS run as a daily diary?

Yes. Schedule it as a recurring questionnaire with a daily completion window and reminders.

Measure pain without anchoring the answer

A VAS with no preset value, on any phone. Free sandbox, no credit card.

Use the VAS template free