Where the words come from
The used-car buyer who cannot be sure the car is not a lemon, the seller's incentive to hide problems, buyers and good sellers becoming reluctant to take part, warranties and guarantees as reassurance — Principles of Economics 2e, OpenStax, licensed CC BY 4.0. https://openstax.org/books/principles-economics-2e/pages/16-1-the-problem-of-imperfect-information-and-asymmetric-information. Changes: Marvin's search condensed and made impersonal; "Consumer Reports" to "reviews"; "a lemon, which is slang for a defective product" put as "a car with hidden faults"; "the more problems the sellers disclose, the lower the car's selling price" kept with light rewording; the warranty definition kept. Akerlof's name, the unravelling argument and its figures, signalling and screening as terms, the UK compulsory motor insurance and MOT history examples, and the recap's account of unravelling are our own wording and not in 2e; British spelling.
Adverse selection and moral hazard defined, low risks declining a premium set for the average risk, and the deductible — Principles of Economics 2e, OpenStax, licensed CC BY 4.0. https://openstax.org/books/principles-economics-2e/pages/16-2-insurance-and-imperfect-information. Changes: Both definitions condensed as noted on the definition block; 2e's hundred-driver example summarised without its figures; "deductibles" given the UK name, excess; the parking example kept; "hidden type" and "hidden action" and the timing test are our own wording, as is the point that a choice of excess levels screens against adverse selection (2e presents the deductible as a moral-hazard remedy only); the mistake note and the recap are our own wording and carry no 2e sourceId; British spelling.
Questions, options, diagrams and feedback are our own. Figures credited to a source above are that source's; every other figure is invented to show the method.