Classic topic evaluation of product manager

During the written test/interview of product managers, we often encounter estimation problems, such as "Please estimate, how many three-star hotels are there in your city?" Or for example, "How many primary schools are there in your city?"

This kind of questions mainly examines the ability of disassembling questions, as well as the ability to quickly analyze problems and logical ability. This does not require you to give an accurate answer (order of magnitude), but requires you to clearly show the process of disassembling and analyzing the problem.

The main answer steps are as follows:

First, analyze the topic and determine the model.

When you first see the topic, you should first stabilize it. Don't feel that the topic can't be started, but you should overcome this mentality. Determine the answer mode according to the content of the question. Generally, I will solve the problem step by step from top to bottom.

For example, "please estimate the profit of the pancake stall at the school gate", and then determine the profit model according to the requirements of the topic, that is, profit = income-cost. Another example is "estimating the number of taxis in Guangzhou", which can determine the model calculation of the number of taxis = the total number of cars * the proportion of taxis to cars.

In the process of finding models, we must be good at using multiplication and division.

Second, according to the logic of parameters, keep digging down.

After determining the model, you should continue to subdivide the parameters in the model until you feel that there is no subdivision.

For example, the profit of pancake fruit is subdivided downwards, monthly profit = daily profit *30 days, daily profit = daily income-cost, daily income = number of pancake fruits sold in one day * price, number of pancake fruits sold in one day = number of pancake fruits sold per hour in peak hours * number of pancake fruits sold per hour in peak hours+low hours, and the parameters in the model are continuously decomposed downwards.

For example, the number of taxis = the total number of cars * the proportion of taxis to cars, and the total number of cars can be decomposed into the total number of cars = the total population * the number of cars per capita.

Third, calculate and consider the edge situation.

Don't underestimate the final calculation process. Although it is only a simple multiplication and division method, the key is not the final result, but your estimation of model parameters. Be sure to explain why you estimate this. Similarly, taking pancake fruit as an example, we can estimate that 30 pancakes will be sold at the peak, so why do we estimate this? We can say that because we make a pancake fruit every 30 seconds, the demand is in short supply at the peak, so we sell 30 pancake fruits every hour at the peak.

You can justify the marginal situation, which may also be the point that the interviewer will ask you after listening to your overall analysis. For example, the question "please estimate the profit of the pancake stall at the school gate" will ask you if you have considered the holiday. We can say that we have taken it into account when calculating the average value, or we can modify our model when calculating to make the result more accurate.

With the answering steps, we are no longer afraid when we get the questions. How to analyze them specifically? I summarized several analysis methods:

1 time analysis

Time analysis, as the name implies, starts from the time dimension and will be disassembled according to time.

For example, "please estimate the income of the pancake vendor at the school gate", the key word is income, and monthly income = daily income *30 days. Starting with the daily income, the daily income can be analyzed by time dimension, which can be divided into peak time and trough time such as breakfast, lunch and dinner time, and analyzed by hour.

2 Spatial analysis

Spatial analysis, that is, disassembling problems from spatial dimensions.

For example, "Please estimate how many primary schools are there in your city?" . According to the spatial division, the city can be divided into several districts, and there are several primary schools in each district on average, that is, the number of primary schools = the number of urban areas * the average number of primary schools in each district.

3 supply and demand analysis

Supply and demand analysis is to see which side is better from the supply side and the demand side.

For example, "estimate the number of taxis in Guangzhou", we start from the supply side and determine the number of taxis provided. We can also start from the demand side, the number of taxis = the number of taxis per day/the number of people served by each car per day, and then continue to decompose the number of taxis per day according to the above steps, and the number of taxis per day = the number of people * the average probability of taxis per person * the average number of taxis per person per day.

Please estimate the profit of the pancake stall at the school gate.

First, determine the model.

Profit = revenue-cost

Second, the parameter subdivision

Monthly profit = daily profit *30 days

Daily profit = daily income-cost

Daily income = quantity of pancake fruit sold in one day * price

Number of pancake fruits sold in one day = number of pancake fruits sold per hour during peak hours * number of pancake fruits sold per hour during peak hours+number of pancake fruits sold per hour during low hours * number of low hours.

Third, calculation

As can be seen from our daily life, the working hours of pancake stalls are from 7 am to 8 pm every day, assuming that vendors rest 1 hour and work 12 hours a day. At the same time, it is assumed that the manufacturer has a busy time of 1 hour every morning, 2 hours at noon and 1 hour at night. During the peak period, because the supply is in short supply, make a pancake fruit every 30 seconds, and sell 30 pancake fruits every hour during the peak period; But at other times, it is the off-season. On average, five pancakes are sold every hour, and one * * * is eight hours.

In this way, vendors can sell 30*4+5*8= 160 pancake fruits a day. Assuming that vendors work 30 days a month, the total number of pancake fruits sold each month is 160 ×30 working days; Suppose each pancake fruit is 6 yuan, then you can calculate the monthly income.

Monthly income:160x30x6 = 28,800 yuan.

Assuming that the raw material cost of each pancake is 2 yuan money, the final profit that vendors can earn in one month is:

Profit: 28,800-160 * 30 * 2 =19,200 yuan.

The above is my summary of the steps and analysis methods to solve the estimation problem. Of course, there are many steps to solve the problem and many analytical methods. Just find the one that suits you. Finally, I hope my summary can be helpful to everyone, thank you.