16 directors, from learning new industries,
new geography, and new functions, to learning how to work well with different people, etc.
Guesstimates Consultants must make educated estimates about the size of a problem
or the impact of a strategy, etc, using their logical ability, general knowledge, and problem-specific learnings (garnered through extensive research and asking good questions.
Illustration Estimate the market size in the US for delivering tomatoes on demand. Top–Down Approach If you are unsure how to start the guesstimate, start big with the basic assumption that the population of the USA is 330 million. According to the Consumer Expenditure Survey, an average household spends $751 on fruits and vegetables yearly. Assuming the average household
size to be three members, a total of $ Bin annual spending in the US. According to the USDA, the share of tomatoes in fruits and vegetables is 5%. Assuming that on-demand delivery of tomatoes will be desirable in large cities whereof the population resides, that reduces our estimate to $ B. Assuming that 20% of households would order tomatoes on demand if offered and that the delivery of tomatoes would increase their consumption by 0-5% (taking a 4%
increase, the final estimate is Mb Bottom-Up Approach
One can also start small by estimating the demand in a large city and extrapolating by considering the total number of large cities. The price of a large tomato in the US is $ 1. Assuming that consumers buy three such tomatoes weekly, the average consumer would buy $ 150 in tomatoes annually (thinking 50 weeks in a year for simplicity. The average population of large US cities is 1 million. Since the average household size is three members and assuming that 20% of households in large cities
would order tomatoes on demand,
66,667 homes would be willing to order tomatoes on demand. Assuming the US has 30 large cities, the final estimate is $ M ($ 150 * 66,667 * 30)