Estimation: Sizing Yearly iPad Unit Sales in the United States

Estimate how many iPads are sold in the United States each year. Talk through how you would structure the estimate, state each assumption as you make it, do the arithmetic out loud, and check whether your final number is believable. ```hint Ownership is not sales Most owners keep a tablet for years, so a count of owners alone overstates what is bought in any single year. Think about what converts a population of owners into a yearly purchase rate, and which buyers besides households you could miss. ``` ### Clarifying Questions - Does the count include only new devices, or also refurbished and second-hand units? - Should purchases by schools, businesses and government agencies count, or only consumers buying for themselves? - Are all current iPad lines (the base model, mini, Air and Pro) in scope, with accessories excluded? ### What a Strong Answer Covers - A clarified scope (new versus used units, consumer versus institutional buyers) before any numbers - A clear equation that turns ownership into yearly purchases, built on segments that do not overlap - Explicit, round, defensible assumptions for each segment, each labeled as an assumption - Clean arithmetic leading to a final number with a sensible range - A sanity check from an independent angle, and a note on which assumption moves the answer most ### Follow-up Questions - Which single assumption changes your answer the most, and how would you get a better number for it? - How would the yearly number change in a recession, and which buyers would react first? - Build a quick top-down estimate starting from Apple's worldwide iPad revenue. Does it agree with your bottom-up number?