Caveats for the customer-facing-calculators brief: every conversion-lift figure is unproven; nearly all are vendor-self-reported

The honest summary of source quality across this brief:

• No independent, peer-reviewed, vendor-neutral benchmark proving website calculators/configurators convert better than static pages appears to exist.
• The closest legitimate academic work — Häubl & Trifts 2000 (Häubl & Trifts 2000 (Marketing Science 19(1):4-21) — controlled lab experiment showing interactive decision aids improve decision quality and reduce search effort) — measures decision quality, not real-world website conversion.
• The famous "2× engagement" figure (Demand Metric 2014 Content & the Buyer's Journey Benchmark Study — vendor-sponsored online opinion survey of 185 marketers; the "2× engagement" headline rounds 70%/36%) is a 2014 marketer-opinion survey sponsored by an interactive-content vendor.
• The 47.3% vs 2.8% figure (Outgrow's "interactive forms 47.3% vs static 2.8%, a 16.9× improvement" is the vendor's analysis of its own customers' 50,000+ forms — not an independent benchmark) is the vendor's analysis of its own platform's forms.
• The form-friction percentages (Practitioner claim: single-field forms ~30-40% conversion, seven-field forms ~5-15% — A/B observation, not controlled study) are a single-source practitioner A/B claim.
• The contractor 20-40% close-rate claim is single-source / vendor.
• The HubSpot 88% bad-experience figure ("88% of online consumers are less likely to return after a bad experience" — originates with HubSpot, often laundered through web-maintenance vendors) is a single vendor stat that has been laundered through maintenance-vendor blogs.
• The McKinsey 83% transparency stat (The "McKinsey: 83% of B2B customers value transparency over brand reputation" stat is not verifiable to any primary McKinsey publication) is not traceable to McKinsey at all.
• The Label Insight 94% stat (Label Insight 2016 Transparency ROI Study — 94% of consumers say they'd be loyal to a brand offering complete transparency (food-category specific, US, 2,000+ consumers)) is real but narrower than usually rendered (food-category).
• The Busso-Galiani "race to the bottom" framing in Kinsta's blog (Correction: Busso & Galiani NBER WP 20054 (2014) actually found competition improved service quality — the popular "race to the bottom" blog reading reverses the finding) reverses the study's actual finding.

Practical posture for Candid: treat every conversion-lift figure in this space as unproven. The case for or against a calculator should be made from the mechanisms (anchoring, qualification, upkeep cost, legal exposure) — not from borrowed stats. See R5 — Disregard vendor-sourced "interactive content converts better" statistics in client conversations.