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Wikie-1 (Heuristics)

The title of this new blog series is also a prophecy about your future. W.i.k.i.e.! Whether you are preparing for exams or working with a company or do your own start-up or choose a career in research - these ideas will be useful for you everywhere.

All of you, at multiple points in your life would have thought or will be forced to tell yourself in frustration - "Wish I knew it earlier!". The intent of this blog series is to inform you about simple things which you will find helpful in life so that you can think clearly and make better decisions in life. We also call these "mental models" or "frameworks".

Whenever you come across information, it is chaotic, confusing, complex and often corrupt. You don't know what to do with it. The ability to be able to analyse and filter this information is no less than a magical power. Believe me! You will wish you knew it earlier.

In the first of this blog series, we have a look at one such brilliant framework called Guesstimation. As you may be able to recognise, it is composed of two simple words - Guess and Estimation - combined together. More accurately it is referred to as Heuristics and it is an extensive set of techniques used to come to an immediate short term approximation.

Funny right? I know, who works like this office? But honestly, that's not very far from what happens in real world situations. On most occasions, there is not enough time and data to be able to arrive at accurate numbers. So you rely on heuristics to get you going.

Practical Example

Assume for a minute you are sitting in front of a customer who wants to know right now if you can complete his 60 crore project within a budget of 50 crores and in less than 6 months. Your competitor says he can do it. What would you do? If you are bad at guesstimations you will start sweating. You start thinking of the possibilities in your mind -

1. if I say yes, my company may lose a lot of money and my boss will fire me in 6 months

2. if I say no, i will lose the project right now and my boss will fire me immediately

Then you take a deep breath and decide to save your job for at least 6 months by saying yes and take a chance. Or you chicken out and disappoint the customer by saying no. Both the outcomes are not desirable. Taking chances is good as long as they are calculated but nobody likes to leave things completely to chance. Nobody likes to lose. These are the situations where heuristics help you get out of a mess. And it is an essential skill!

Heuristics and Guesstimations

The study of heuristics is important because it reduces mental load to make decisions. Those who make easier and accurate predictions save time & energy, get more work done, make lesser mistakes and have higher chances of success. But it requires you to be conscious and pick up information from your surroundings.

Heuristics have a simple 4 step process -

Understand Problem >> Select Method >> Solve >> Adjust

Some basic methods to use heuristic principles are provided below with examples.

1. Division

Divide complex problem into parts, solve them separately and combine the results Example - Divide and conquer is the most famous heuristic strategy in this category. Examinations are the best application to consider. You get the question paper and look at the questions first. You distribute the questions into categories based on your knowledge - 1. Easy : you answer these questions first because you know the answers already and finish them at lightning speed from memory and save as much time as possible 2. Work Outs : you know the method but need to work out the correct answer by applying your mind and focus, these are the questions you attempt next 3. Difficult : these questions you are not confident about and need to apply estimations and need as much time as possible to think in detail so you attempt them at the end by saving time.

Without counting you can even estimate number of cars running in London. :) Watch!

2. Induction

Look for a smaller similar problem and use it solve the bigger problem.

Example - Interviewer asks you - how much tea does India consume in total per year? Weird question, would someone ask me that? Yes, because it is possible to estimate it. How?

Step 1: In my family I know everyone drinks tea at least twice a day - morning before breakfast and evening snack time. Some tea lovers might be having 3 times a day, some only once a day and some don't drink tea at all like in Tamil Nadu filter coffee is more prevalent. So on average I assume 1 tea cup per day per person.

Step 2: When we make tea for 1 person we use approximately 1 teaspoon of tea leaves. How much would it be in grams? I would approximate 5 grams.

Step 3: There are total of 1.35E9 people in India. Since children & youngsters usually do not drink tea, I will consider only half of the people i.e. 6.75E8 people. Then if everyone on average drinks at least 1 tea cup every day - 3.375E9 grams of tea must be consumed or approximately 3.4E6 kilograms of tea per day.

Step 4: So in one year we can multiply by 365 days i.e. 1.24E9 kg of tea or 1.2 billion kg of tea consumption per year in India.

Let's check how accurate was our guesstimation by searching the internet.

Approximately 1 billion kg of tea was consumed in 2018. So our guesstimation from my own small house brought us up to right order of magnitude of prediction for the whole of India. Not bad, right? When you pick numbers and combine them smartly, errors get absorbed in the overall induction. But that requires a keen sense of observation, intuition and consciousness about our surroundings.


Reducing less important constraints and factors to simplify the problem and solve it. Example - Elimination is one of the most common application of this heuristic.

When you enter Class XI, XII - most of you have to take tuitions for board exams, NEET and / or JEE. You have a choice of taking tuitions individually for each subject or taking up coaching with all subjects combined. How do you make that choice? Physics, Chemistry, Biology, Mathematics, Computer Science - so many subjects.

Going to a coaching class makes you comfortable because all subjects are taught in the same centre. Individual coaching will require you traveling from one centre to another - physics to math to chemistry to computer science to biology. 5 different tuitions with 15-20 mins of travel between each. This means almost 1-1.5 hours of extra travel everyday.

But there are so many factors - travel time, classroom comfort, study material, test series, choice of tutor, personal attention. How do you decide? So we think using reduction. Since study material & test series are available without coaching also, we can eliminate these factors. Classroom comfort is irrelevant to me and I can study with just a table & chair as well so I eliminate that too. We are left with 3 factors now - travel time, choice of tutor, personal attention.

"Travel Time of extra one hour every day" versus "choice of best tutors available in each subject and personal attention from them". This is now a much more simplified problem of comparison. You can make the decision much more easily than before. This is how reduction works.

Here is an interesting video about the interesting "Science of Thinking" you can watch. Enjoy!

Also a guesstimate problem for you. Comment with your solution. What is the total value of clothes sold in Dehradun every year if there are 20 lac people living there?

PS: This is a series of blog posts every weekend - Saturday and Sunday - for my students to learn and benefit from. A way for us to remain connected beyond school and tuition classes. I welcome suggestions from my students about the topics they would like me to research and write about. If your suggestion is selected, I will mention your name in credits of the blog. Please like, share and subscribe to the blog for more grown-up advice. Stay safe and stay connected always :).

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Monkv Yasaa
Monkv Yasaa
09 de abr. de 2022

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