The Harvard H Sweater is desirable, especially among Harvard students, because it is both limited in supply (scarcity principle), utilizes the price-qulaity heuristic (retails for $129.99), and has a sense of nostalgia to it. The marketing around it utilizes the word “tradition” to make this product feel as if it has “stood the test of time” and is well-established but also uses current and well-known Harvard students as models to give it a fresh and new appeal. Additionally, only 100 are ordered each year and they are known to sell out within a week so a sense of urgency is created for buyers. This limited availability makes the product exclusive (not to mention that it represents a somewhat exclusive university) and thus the sweater is desirable.
