Do you want to know “how banks rate you when you borrow money from banks”?

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Hi friends,  I am Toshi, This is my weekly letter. This week’s topic is “how banks rate you when you borrow money from banks”. When we want bank loans, it is good that we can borrow the amount of money we need,  with a lower interest.  Then I am wondering how banks decide who can borrow the amount of money requested with lower interests. In other words, how banks assess customer’s credit worthiness.  The answer is “Classification”.  Let me explain more details. To make the story simple,  I take an example of  unsecured loans, loans without collateral.

 

1.  “Credit risk model” makes judgements to lend

Now many banks prepare their own risk models to assess credit worthiness of customers.  Especially global banks are required to prepare the models by regulators, such as BIS, FSA and central banks. Major regional banks are also promoted to have risk models to assess credit worthiness.  Regulations may differ from countries to countries,  by size of banks.  But it is generally said that banks should have their risk models to enhance credit risk management.  When I used to be a credit risk manager of the Japanese consumer finance company, which is one of  the group companies in the biggest financial group in Japan,  each customer is rated by credit risk models. Good rating means you can borrow money with lower interest. On the other hand, bad rating means you can borrow only limited amount of money with higher interest rate or may be rejected to borrow. From the standpoint of management of banks, it is good because banks can keep consistency of the lending judgements to customers among the all branches.  The less human judgement exists, the more consistency banks keep.  Even though business models may be different according to strategies of banks, the basic idea of the assessment of credit worthiness is the same.

 

2. “Loan application form” is a starting point of the rating process

So you understand credit risk models play an important role. Next, you may wonder how rating of each customer is provided.  Here “classification” works. Let me explain about this.  When we try to borrow money,  It is required to fill “application forms”. Even though the details of forms are different according to banks,  we are usually asked to fill “age” “job title” “industry” “company name” “annual income” “owned assets and liabilities” and so on.   These data are input into risk models as “features”.   So each customer has a different value of “features”.  For example, someone’s income is high while others income is low.   Then I can say  “Features”of each customer can explain credit worthiness of each customer.   In other words,  credit risk model can “classify”  customers with high credit worthiness and customers with low credit worthiness by using  “features”.

 

3.  Rating of each customer are provided based on “probability of default

Then let us see how models can classify customers in more details. Each customer has values of “features”  in the application form. Based on the values of “features”, each customer obtains his/her own “one value”.  For example, Tom obtains “-4.9” and Susum obtains “0.9” by adding “features” multiplied with “its weight”.  Then we can obtain “probability of default” for each customer.  “Probability of default” means the likelihood where the customer will be in default in certain period, such as one year. Let us see Tom’s case. According to the graph below,  Tom’s probability of default, which is shown in y-axis, is close to 0.  Tom has a low “probability of default”. It means that he is less likely to be in default in the near term. In such a case,  banks provide a good rating to Tom. This curve below is called “logistic curve” which I explained last week. Please look at my week letter on 23 April.

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Let us see Susumu’s case. According to the graph below,  Susumu’s probability of default, which is shown in y-axis, is around 0.7, 70%.  Susumu has a high probability of default. It means that he is likely to be in default in the near term. In such a case,  banks provide a bad rating to Susumu. In summary,  the lower probability of default is,  the better rating is provided to customers.

 

logistic1

Although there are other methods  of “classification”,  logistic curve is widely used in the financial industry as far as I know. In theory, the probability of default can be obtained for many customers from individuals to big company and sovereigns, such as “Greeks”.  In practice, however, more data are available in loans to individuals and small and medium size enterprises (SME) than loans to big companies.  The more data are available, the more accurately banks can assess credit worthiness. If there are few data about defaults of customers in the past,  it is difficult to develop credit risk models effectively. Therefore, risk models of individuals and SMEs might be easier than risk models of big companies as more data are usually available in loans to individuals and SMEs.

I hope you can understand the process to rate customers in banks. Data can explain our credit worthiness, maybe better than we do. Data about us is very important when we try to borrow money from banks.

The reason why computers may replace experts in many fields. View from “feature” generation.

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Hi friends, I am Toshi. I updated my weekly letter.  Today I explain 1. How classification, do or do not, can be obtained with probabilities and 2. Why computers may replace experts in many fields from legal service to retail marketing.   These two things are closely related to each other. Let us start now.

 

1.  How can classification be obtained with probabilities?

Last week, I explained that “target” is very important and “target” is expressed by “features”.  For example Customer “buy” or “not buy” may be expressed by customers age and  the number of  overseas trips a year.  So I can write this way : “target” ← “features”.   This week, I try to show you the value of “target” can be a probability, which is  a number between 0 and 1.  If the “target” is closer to “1”,  the customer is highly likely to buy.   If the target is closer to “0”,  the customer is less likely to buy.   Here is our example of “target” and “features” in the table below.

customer data

I want  Susumu’s value of the “target” to be close to “1” in calculations by using “features”.  How can we do that?   Last week we added “features” with“weight” of each feature.   For example  (-0.2)*30+0.3 *3+6,  the answer is 0.9.  “-0.2″ and “0.3” are the weight for each feature respectively. “6” is a kind of adjustment.  Next let us introduce this curve below. In the case of Susumu, his value from his features is 0.9. So let us put 0.9 on the x-axis, then what is the value of y? According to this  curve, the value of y is around 0.7. It means that  Susumu’s probability of buying products is around 0.7.  If probability is over 0.5, it is generally considered that customer is likely to buy.

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In the case of Tom, I want his value of the “target” to be close to “0” in calculations by using “features”.  Let us add his value of features as follows  (-0.2) *56+0. 3 *1+6,  the answer is -4.9.  His value from his features is -4.9. So let us put  -4.9 on the x-axis, then what is the value of y?  According to this curve, Tom’s probability of buying products is almost 0. Unlike Susumu’s case, Tom is less likely to buy.

logistic2

This curve is called “logistic curve“.   It is interesting that whatever value “x” takes, “y” is always between 0 and 1.  By using this curve, everyone can have the value between 0 and 1, which is considered as the probability of the event. This curve is so simple and useful that it is used in many fields.  In short, everyone has a probability of buying products, which is expressed as the value of “y”.  It means that we can predict who is likely to buy in advance as long as “features”are obtained! The higher value customers have, the more likely they will buy the products.

 

 

2.  Why may computers replace experts in many fields?

Now you understand what are”features”.  “Features” generally are set up based on expert opinion. For example, if you want to know who is in default in the future, “features”needed are considered “annual income”, “age”, “job”, “the past delinquency” and so on. I know them because I used to be a credit risk manager in consumer finance company in Japan.  Each expert can introduce the features in the business and industries.  That is why the expert’s opinion is valuable, so far. However, computers are also creating their features based on data. They are sometimes so complex that no one can understand them. For example, ” -age*3-number of jobs in the past” has no meaning for us. No one knows what it means. But computers do. Sometimes computers can predict “target”, which means “do” or “not do” with their own features more precisely than we do.

 

In the future,  I am sure much more data will be available to us.  It means computers have more chance to create better “features” than experts do. So experts should use the results of predictions by computers and introduce them into their insight and decisions in each field.  Otherwise, we cannot compete with computers because computers can work 24 hours/day and 365 days/year. It is very important that the results of predictions should be used effectively to enhance our own expertise in future.

 

 

Notice: TOSHI STATS SDN. BHD. and I, author of the blog,  do not accept any responsibility or liability for loss or damage occasioned to any person or property through using materials, instructions, methods, algorithm or ideas contained herein, or acting or refraining from acting as a result of such use. TOSHI STATS SDN. BHD. and I expressly disclaim all implied warranties, including merchantability or fitness for any particular purpose. There will be no duty on TOSHI STATS SDN. BHD. and me to correct any errors or defects in the codes and the software.

Easy way to understand how classification works without formula! no.1

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Hello, I am Toshi. Hope you are doing well. Last week  I introduced “classification” to you and explained it can be applied to every industry. Today I would like to explain how it works step by step  this week and next week. Do not worry, no complex formula is used today.  It is easier than making pancakes with fry pan!

I understand each business manager have different of problems and questions. For example, if you are a sales manager in retail, you would like to know who is likely to buy your products.  If you are working in banks, you want to know who will be in default. If you are in the healthcare industries, who is likely to have diseases in future.  It is awesome for your business if we can predict what happens with certainty in advance.

These problems look like different from each other. However, they are categorized as same task called “classification” because we need to classify “do” or “do not”.  For sales managers, it means that “buy” or “not buy”. For managers in banks,  “in default” or “not in default”. In personnel in legal service, “win the case” or “not win the case”.  If predictions about “do” or “do not” can be obtained in advance.  It can contribute to the performance  of your businesses. Let us see how it is possible.

 

1.  “target” is significantly important

We can apply “do” or ” do not” method to all industries. Therefore, you can apply it to your own problems in businesses.  I  am sure you are already interested in  your own “do” or ” do not”.   Then let us move on to data analysis.  “Do” or “do not” is called “target” and has a value of  “1” or “0”.  For example, I bought premium products in a retail shop,  In such a case,  I have “1” as  a target.  On the other hand, my friend did not buy anything there.  So she has “0”  as a target.   Therefore  everyone should have “1” or “0” as a target.   It is very important as a starting point.  I recommend to consider what is a good  “target” in your businesses.

 

2.  What are closely related to “target”?

This is your role because you have expertise in your business.  It is assumed that you are sales manager of retail fashion. Let us imagine what are closely related to the customer’s “buy” or “not buy”.  One of them may be customers’ age because younger generation may buy more clothes than senior.  Secondly, the number of  overseas trips a year because the more they travel overseas, the more clothes they buy.  Susumu, one of my friends, is 30 years old and travels overseas three times a year.  So his data is just like this : Susumu  (30, 3).  These are called “features”.   Yes, everyone has different values of the features. Could you make your own values of features by yourself?  Your value of the features must be different from (30,3).  Then, with this feature (30, 3),  I would like to express “target” next.  (NOTE: In general,  the number of features is far more than two. I want to make it simple to understand the story with ease.)  Here is our customer data.

customer data

3.  How “targets” can be expressed with “features”?

Susumu has his value of features (30, 3).  Then let us make the sum of  30 and 3. The answer is 33.  However, I do not think it works because each feature has same impact to “target”.  Some features must have more impact than others. So let us introduce “weight” of each feature.   For example  (-0.2)*30+0.3 *3+6,  the answer is 0.9.  “-0.2” and “0.3” are the weight for each feature respectively. “6” is a kind of adjustment. This time it looks better as “age” has a different impact from “the number of travels”against “target”.  So “target”, which means in this case Susume will buy or not,  is expressed with features, “age” and  “the number of travels”.  Once it is done, we do not need to calculate by ourselves anymore as computers can do that instead of us. All we have to know is “target” can be expressed with “features”.  Maybe I can write this way : “target” ← “features”.   That is all!

 

 

Even if the number of features is more than 1000, we can do the same thing as above.  First, put the weight to each feature, second, sum up all features with each weight.  Therefore, you understand how a lot of data can be converted to  just “one value”.  With one value, we can easily judge whether Susumu is likely to buy or not.  The higher value he has,  the more likely he will buy clothes. It is very useful because it enables us to intuitively know whether customers will buy or not.

Next week I would like to introduce “Logistic regression model” and explain how it can be classified quantitatively.   See you next week!

“Classification” is significantly useful for our business, isn’t it?

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Hello, I am Toshi. Hope you are  doing well. Now I consider how we can apply data analysis to our daily businesses.  So I would like to introduce “classification” to you.

If you are working in marketing/sales departments, you want to know who are likely to buy your products and services. If you are in legal services, you would like to know who wins the case in a court. If you are in financial industries, you would like to know who will be in default among your loan customers.

These cases are considered as same problems as “classfication”.  It means that you can classify a thing or an event you are interested in from all populations you have on hand.  If you have data about who bought your products and services in the past, we can apply “classification” to predict who are likely to buy and make better business decisions. Based on the results of classification,  you can know who is likely to win cases and who will be in default with a numerical measure of certainty,  which is called “probability”.  Of course, “classification” can not be a fortune teller.  But “classification” can provide us who is likely to do something or what is likely to occur with some probabilities.  If your customer has 90% of probabilities based on “classification”, it means that they are highly likely to buy your products and services.

 

I would like to tell several examples of “classification” for each business. You may want to know the clues about the questions below.

  • For the sales/marketing personnel

What is the movie/music in the Top 10 ranking in the future?

  • For personnel in the legal services

Who wins the cases ?

  • For personnel in the financial industries or accounting firms

Who will be in default in future?

  • For personnel in healthcare industries

Who is likely to have a disease or cure diseases?

  • For personnel in asset management marketing

Who is rich enough to promote investments?

  • For personnel in sports industries

Which team wins the world series in baseball?

  • For engineers

Why was the spaceship engine exploded in the air?

 

We can consider a lot of  examples more as long as data is available.  When we try to solve these problems above,  we need data in the past, including the target variable, such as who bought products, who won the cases and who was default in the past.  Without data in the past, we can predict nothing. So data is critically important for “classification” to make better business decisions.   I think data is “King”.

 

Technically, several methods are used in classification.  Logistic regression,  Decision trees,  Support Vector Machine and Neural network and so on. I recommend to learn Logistic regression first as it is simple, easy to apply real problems and can be basic knowledge to learn more complex methods such as neural network.

 

I  would like to explain how classification works in the coming weeks.  Do not miss it!  See you next week!

Is it possible to raise the quality of services if computers can talk to you?

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When you go to Uniqlo,  people of Uniqlo talk to you and advise how you can coordinate your favorite fashion.  When you go to hospitals, doctors ask you what your condition is and advise you what you should do in order to be healthy.  Then let us consider whether computers can talk to you and answer your questions, instead of a human being.

It is the first step to know the customers in service industries,  students in education.  So there are many people working to face with customers and students. If computers can face with customers and students,  it means that quality of services dramatically is going up because computers are cost-effective and operate 24hours per day, 365 days per year without rest time.

 

I like taking courses in open online courses.  It is very convenient as we can look at courses whenever we want as long as internet connection is available.  But the biggest problem is that there are no teachers to be asked for each learner when you want to ask.  This description explains this problem very well.

Because of the nature of MOOC-style instruction (Massive Open Online Course), teachers cannot provide active feedback to individual learners. Most MOOCs have thousands of learners enrolled at the same time and engaging personally with each learner is not possible.”

When I cannot understand the course lectures and solve the problems in exams by myself, it is very difficult to continue to learn because I feel powerless.  This is one of the reasons why completion rate is very low in open online courses (usually less than 10%).  If you need assistance from instructors,  you should pay fees which are not cheep for people in developing countries. I want to change this situation.

 

A technology called “Machine learning” may enable us to enjoy conversations with computers cross industries from financial to education.  Computers can understand what you ask and provide answers in real-time basis.  It takes some time to develop to make computers more sophisticated, so that computers can answer exactly what you want.  This is like a childhood.  At the beginning, there is very little knowledge so It may be difficult to answer questions. Then computers start learning from interactions with human.  The more knowledge they have,  the more sophisticated their answer is.

So I would like to start to examine how computer is learning in order to provide sophisticated answers to learners and customers. If computers obtain enough knowledge effectively, they can talk to you and enjoy conversations with you.  I hope computers can be good partners to us.