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Van Westendorp Price Sensitivity Meter

Van Westendorp Price Sensitivity Meter

Overview

概述

Van Westendorp PSM uses four price perception questions to identify an acceptable price range through intersection analysis. Produces: Point of Marginal Cheapness (PMC), Point of Marginal Expensiveness (PME), Indifference Price Point (IPP), and Optimal Price Point (OPP). Requires survey data from 100+ respondents.
Van Westendorp PSM通过四个价格感知问题，借助交叉分析确定可接受的价格区间。输出结果包括：边际低价点（PMC）、边际高价点（PME）、无差异价格点（IPP）和最优价格点（OPP）。需要100份以上受访者的调研数据。

When to Use

适用场景

Trigger conditions:
  • Setting initial price for a new product or service
  • Identifying the acceptable price range from consumer perception
  • Quick pricing research without complex experimental design
When NOT to use:
  • When you need to measure attribute trade-offs (use conjoint analysis)
  • When you need demand curve estimation (use price elasticity)
触发条件：
  • 为新产品或服务设定初始价格
  • 从消费者感知角度确定可接受价格区间
  • 无需复杂实验设计的快速定价调研
不适用场景：
  • 需要衡量属性取舍时（请使用联合分析）
  • 需要估算需求曲线时（请使用价格弹性分析）

Algorithm

算法

IRON LAW: Van Westendorp Identifies an ACCEPTABLE Range, Not Optimal Price
It doesn't account for competition, costs, or willingness to pay at
scale. It tells you WHERE prices are perceived as reasonable, not
what maximizes revenue. Use as input to pricing strategy, not as the
final answer.
IRON LAW: Van Westendorp Identifies an ACCEPTABLE Range, Not Optimal Price
It doesn't account for competition, costs, or willingness to pay at
scale. It tells you WHERE prices are perceived as reasonable, not
what maximizes revenue. Use as input to pricing strategy, not as the
final answer.

Phase 1: Input Validation

阶段1：输入验证

Survey 100+ target customers with four questions at various price points:
  1. Too cheap (quality suspect)? 2. A bargain (great deal)? 3. Getting expensive (but would consider)? 4. Too expensive (would not buy)? Gate: 100+ responses, all four curves plottable.
针对100+目标客户开展调研，设置四个不同价格点的问题：
  1. 价格过低（怀疑质量）？ 2. 价格实惠（划算）？ 3. 价格偏高（但仍会考虑）？ 4. 价格过高（不会购买）？ 准入要求： 100份以上回复，四条曲线均可绘制。

Phase 2: Core Algorithm

阶段2：核心算法

  1. For each price point, compute cumulative percentages for each question
  2. Plot four curves: "too cheap" (descending), "cheap/bargain" (descending), "expensive" (ascending), "too expensive" (ascending)
  3. Find intersections:
    • OPP = intersection of "too cheap" and "too expensive" (optimal price point)
    • IPP = intersection of "cheap" and "expensive" (indifference price point)
    • PMC = intersection of "too cheap" and "expensive" (marginal cheapness)
    • PME = intersection of "cheap" and "too expensive" (marginal expensiveness)
  4. Acceptable range = [PMC, PME]
  1. 针对每个价格点，计算每个问题的累积百分比
  2. 绘制四条曲线：“价格过低”（下降趋势）、“价格实惠”（下降趋势）、“价格偏高”（上升趋势）、“价格过高”（上升趋势）
  3. 寻找交叉点：
    • OPP = “价格过低”与“价格过高”曲线的交叉点（最优价格点）
    • IPP = “价格实惠”与“价格偏高”曲线的交叉点（无差异价格点）
    • PMC = “价格过低”与“价格偏高”曲线的交叉点（边际低价点）
    • PME = “价格实惠”与“价格过高”曲线的交叉点（边际高价点）
  4. 可接受价格区间 = [PMC, PME]

Phase 3: Verification

阶段3：验证

Check: PMC < OPP < IPP < PME (expected ordering). All intersections exist within surveyed range. Gate: Four-point ordering is logical, range is commercially viable.
检查：PMC < OPP < IPP < PME（预期顺序）。所有交叉点均在调研价格范围内。 准入要求： 四点顺序符合逻辑，区间具备商业可行性。

Phase 4: Output

阶段4：输出

Return price points and acceptable range.
返回价格点及可接受价格区间。

Output Format

输出格式

json
{
  "price_points": {"opp": 299, "ipp": 349, "pmc": 199, "pme": 449},
  "acceptable_range": {"min": 199, "max": 449},
  "metadata": {"respondents": 250, "currency": "TWD", "product": "..."}
}
json
{
  "price_points": {"opp": 299, "ipp": 349, "pmc": 199, "pme": 449},
  "acceptable_range": {"min": 199, "max": 449},
  "metadata": {"respondents": 250, "currency": "TWD", "product": "..."}
}

Examples

示例

Sample I/O

输入输出示例

Input: 200 survey responses for a SaaS product, price range tested: $5-$50/month Expected: PMC=$12, OPP=$18, IPP=$22, PME=$35. Acceptable range: $12-$35.
输入： 针对某SaaS产品的200份调研回复，测试价格区间：每月5-50美元 预期输出： PMC=12美元，OPP=18美元，IPP=22美元，PME=35美元。可接受价格区间：12-35美元。

Edge Cases

边缘情况

InputExpectedWhy
Curves don't intersectExtend surveyed rangePrice points tested were too narrow
IPP < OPPUnusual but possibleCheck data quality, may indicate confused respondents
Very wide rangeLow price sensitivityProduct category has high tolerance
输入预期结果原因
曲线无交叉点扩大调研价格区间测试的价格点范围过窄
IPP < OPP虽不常见但有可能检查数据质量，可能表明受访者存在混淆
区间过宽价格敏感度低产品类别具备较高价格容忍度

Gotchas

注意事项

  • Hypothetical bias: People say they'd pay more than they actually would. Van Westendorp systematically overestimates willingness to pay.
  • No competitive context: Respondents answer in isolation. Real purchase decisions consider alternatives. Supplement with competitive analysis.
  • Sample representativeness: Results are only valid for the surveyed population. B2B vs B2C, early adopters vs mainstream — all give different ranges.
  • Newton-Miller-Smith extension: Add purchase intent questions at OPP and IPP for more actionable revenue estimates. Standard Van Westendorp alone lacks this.
  • Product must be understood: Respondents need to understand what they're pricing. For novel products, include a clear concept description.
  • 假设偏差：人们声称愿意支付的价格通常高于实际支付意愿。Van Westendorp会系统性高估支付意愿。
  • 无竞争背景：受访者是孤立作答的，而实际购买决策会考虑替代选项。需结合竞争分析补充信息。
  • 样本代表性：结果仅对调研人群有效。B2B与B2C、早期采用者与主流用户——不同群体得出的区间差异较大。
  • Newton-Miller-Smith扩展：在OPP和IPP价格点添加购买意向问题，以获取更具可操作性的收入估算。标准Van Westendorp本身不具备此功能。
  • 产品需清晰易懂：受访者需要了解所定价的产品。对于创新性产品，需包含明确的概念说明。

References

参考资料

  • For Newton-Miller-Smith purchase intent extension, see 
    references/nms-extension.md
  • For survey design best practices, see 
    references/survey-design.md
  • 关于Newton-Miller-Smith购买意向扩展，请参见
    references/nms-extension.md
  • 关于调研设计最佳实践，请参见
    references/survey-design.md