Spiegel 2017 (Northwestern) — 5 reviews = 270% purchase likelihood lift; 380% for higher-priced

Claim: Northwestern University Medill Spiegel Research Center study (June 2017, with PowerReviews; research director Professor Edward Malthouse) found:

• "The purchase likelihood for a product with 5 reviews is 270% greater than the purchase likelihood of a product with no reviews."
• Higher-priced/higher-consideration products: displaying reviews raised conversion 190% for a lower-priced product but 380% for a higher-priced product.
• "When the price is higher, there is more risk involved in the consumer's decision."

Source: Spiegel Research Center, Northwestern University. Academic.

Confidence: Verified.

Why this matters for Candid: Independent corroboration of Luca's effect in a different research design + domain. The 380% figure for higher-priced products is particularly relevant for trades / professional services / B2B.