4Ps and 4Cs of marketing
The 4Ps (product, price, place, promotion) are E. Jerome McCarthy's 1960 checklist of the marketing mix; the 4Cs (consumer wants, cost, convenience, communication) are Robert Lauterborn's 1990 rewrite of the same four levers from the buyer's side. Each C pairs with one P, so they are two views of one set of decisions, not rival models. Good as a completeness check, weak as strategy: neither says who to target or why they should pick you over the brand they already buy.
Where it's used
Used in marketing plans, launch checklists and marketing courses to check that product, price, distribution and communication were each decided on purpose. Good for auditing a plan from the customer's side, once targeting and positioning are already settled.
Example
Same four decisions, read from the buyer's chair
Illustrative scenarioA meal-kit startup writes its plan in Ps: a three-recipe box, 59 EUR a week, delivered on Thursdays, promoted with Instagram ads. Rewritten in Cs, two gaps show up. The real cost to the customer includes a weekly subscription that is easy to forget, and convenience breaks for anyone who is not home on Thursday. The team adds a pause button and a pickup point, two fixes the 4Ps checklist had already marked as done.