Willingness-to-Pay Interview Template (Van Westendorp + AI)

The Bottom Line

The Van Westendorp Price Sensitivity Meter (PSM) is the most-used pricing interview framework in the world — but it has always been a survey, which means you get four numbers and zero context. This template shows you how to run Van Westendorp as an AI-moderated interview instead, so every price point comes with the qualitative reasoning behind it. With a tool like Koji, the four core price questions auto-aggregate into distribution charts, while open-ended follow-ups capture the "why" — without you running a single live call.

Clone the structured questions below, paste them into a new Koji study, share the link, and you have a live willingness-to-pay study running in 30 minutes.

Why Van Westendorp Survives in 2026

Most pricing methods have a fatal flaw: they ask a single question ("What would you pay?") and lock the respondent into a number. Van Westendorp asks four questions that triangulate the acceptable price range:

1. At what price would this be so expensive that you would not consider buying it? (too expensive)
2. At what price would this start to feel expensive — but you would still consider it? (expensive)
3. At what price would this start to feel like a great deal? (good value / cheap)
4. At what price would this be so cheap that you would question its quality? (too cheap)

Plot the four cumulative curves and you get four canonical points: Point of Marginal Cheapness (PMC), Point of Marginal Expensiveness (PME), Optimal Price Point (OPP), and Indifference Price Point (IPP). The acceptable price range sits between PMC and PME, and most teams anchor their list price at OPP.

The reason Van Westendorp survives in 2026 — when most "ask the customer" pricing methods have been discredited — is that it forces respondents to think about price as a multidimensional signal (quality, fit, alternatives) rather than a single willingness number.

The Limit of Survey-Based Van Westendorp

The classic survey version has three weaknesses:

1. No reasoning. You see that someone said €40 was "too expensive" but never learn whether their reference price was a competitor, a budget constraint, or a quality assumption.
2. No segmentation depth. You can cross-tabulate by demographic, but you cannot probe why a segment behaves differently.
3. Anchoring drift. Respondents tend to anchor all four prices off whichever they answer first.

An AI-moderated interview fixes all three. The AI asks each price question, listens to the participant’s justification, and probes follow-ups to surface the underlying reference point. Anchoring drift drops because the conversation breaks the survey rhythm.

The Template (Copy/Paste Into Koji)

Here is the full structured-questions interview plan. Each question carries a stable ID, a question type, and probing config that drives Koji’s AI moderator behavior.

Section 1 — Context priming (1 question)

ID: q1_context
Type: open_ended
Text: Walk me through the last time you bought a product or service in this category. What were you trying to solve, and how did you decide what to spend?
Probing: maxFollowUps: 2
Why: Anchors the participant in real purchase context before pricing — reduces hypothetical bias.

Section 2 — Van Westendorp price points (4 questions)

ID: q2_too_expensive
Type: scale
Text: At what price would this product be SO EXPENSIVE that you would not consider buying it?
Config: scaleMin: 0, scaleMax: 200 (currency: EUR — adjust to your unit and range)
Probing: maxFollowUps: 1, anchor: true (asks "What would change that?")
Display: slider

ID: q3_expensive
Type: scale
Text: At what price would this start to feel expensive — but you would still consider buying it after some thought?
Config: scaleMin: 0, scaleMax: 200
Probing: maxFollowUps: 1, anchor: true
Display: slider

ID: q4_good_value
Type: scale
Text: At what price would this feel like a great deal — high quality for the money?
Config: scaleMin: 0, scaleMax: 200
Probing: maxFollowUps: 1, anchor: true
Display: slider

ID: q5_too_cheap
Type: scale
Text: At what price would this be SO CHEAP that you would question whether it is high quality?
Config: scaleMin: 0, scaleMax: 200
Probing: maxFollowUps: 1, anchor: true
Display: slider

Section 3 — Reference points (1 question)

ID: q6_reference
Type: open_ended
Text: When you were thinking about those prices, what other product, service, or budget were you comparing them to?
Probing: maxFollowUps: 2
Why: Surfaces the actual reference price the participant was anchoring on.

Section 4 — Purchase intent (1 question)

ID: q7_intent
Type: single_choice
Text: At a price of [your hypothesized list price], how likely would you be to purchase?
Config: options: ["Definitely buy", "Probably buy", "Might buy", "Probably not buy", "Definitely not buy"]
Probing: maxFollowUps: 1

Section 5 — Feature bundle sensitivity (optional, 1 question)

ID: q8_bundle
Type: ranking
Text: If we had to remove features to hit a lower price, which would you keep first and which would you drop first?
Config: options: ["Feature A", "Feature B", "Feature C", "Feature D", "Feature E"]
Probing: maxFollowUps: 0
Why: Reveals price-feature elasticity beyond the single-product Van Westendorp.

That is 8 questions, ~10 minutes of participant time, and produces a complete Van Westendorp dataset plus qualitative reasoning.

How Koji Auto-Aggregates the Result

The four scale questions produce numeric distributions that Koji charts automatically as Van Westendorp curves. The single_choice purchase-intent question produces a frequency bar chart. The ranking question produces an average-position ranked list. The open_ended questions produce themed summaries with verbatim quotes.

In other words: the moment your sample size hits ~30 participants, your Van Westendorp price points are already plotted in the report. No spreadsheet, no manual coding, no analyst hours.

For structured questions like these four scales, Koji’s per-question aggregation is what turns a 30-hour analyst job into a real-time dashboard.

Recommended Sample Size

Van Westendorp produces stable price points around n=80 to n=150 for a single segment. For multi-segment pricing (e.g., enterprise vs SMB vs prosumer), aim for n=80 per segment. Because Koji interviews are async and self-serve, you can hit those numbers in days rather than weeks.

A rough budget on Koji’s Interviews plan:

• 80 text interviews = 80 credits → 1 month of the Interviews plan (€79) covers it with one credit left over.
• 80 voice interviews = 240 credits → €79 plan + 161 overage × €1 = €240 total.

Compare that to a traditional Van Westendorp study with a panel platform: 80 × (€40 recruiting + €25 incentive) = €5,200 minimum, before any moderator or analysis time.

Common Mistakes to Avoid

1. Asking Van Westendorp without context. Pure hypothetical pricing produces noise. The "context priming" question (q1) is non-optional.
2. Letting price points cross. If a participant says "too expensive: €30" and "expensive: €50", flag and re-ask. Koji’s probing follow-up catches this automatically.
3. Running on the wrong audience. Van Westendorp only works on people who could realistically buy your product. Use a screener-questions-guide flow to filter.
4. Assuming OPP equals list price. OPP is a starting hypothesis; validate against conversion data.
5. Skipping the reference question (q6). Without it, you see prices but not the mental anchors driving them.

What to Do With the Results

When the report is ready:

1. Plot the four cumulative curves (Koji does this automatically for scale questions).
2. Identify PMC, PME, OPP, IPP at the curve intersections.
3. Read the q6 reference theme to understand what alternatives anchor your pricing.
4. Cross-tab purchase intent (q7) by segment to find the segment where intent peaks at OPP.
5. Use the ranking output (q8) to design good/better/best tiers.

The whole synthesis takes 30–60 minutes, not 30 hours.

Related Resources

• Structured Questions Guide — the 6 question types that drive auto-aggregation
• Pricing Research Interviews — broader pricing research methodologies
• Pricing Research Survey Guide — survey-only counterpart
• Screener Questions Guide — filtering participants for pricing studies
• Generating Research Reports — how Van Westendorp curves render in reports
• User Research Cost Calculator — budgeting an 80-participant pricing study