What is social credit score | 什么是社会信用分

Social credit score 社(shè)会(huì)信(xìn)用(yòng)分(fēn) means rating how trustworthy you are based on your spending habits, social connections and your online behavior on social media. Traditional credit scores are what lending institutions use to judge how likely you will pay back the money before they lend you. Traditional credit score use information such as whether and how long you have a job, how much money you owe relative to how much you earn, and so on. Social credit is being used in similar ways with a different set of data. Tencent Credit 腾讯信用分 and Sesame Credit 芝麻信用分 are the prime examples.

For example, social credit score can be like a test score number that ranges between 300 and 850 and made up of five dimensions/categories 5 个维度:

  • social connections
  • consumption behavior
  • security
  • wealth
  • compliance

WSJ reported in 2016 on social credit in China with an article title “China’s New Tool for Social Control: A Credit Rating for Everything“. The words “social control” and “Big Brother” have bad connotations. However, politics aside, we do appreciate people who have good social credit.

What can social credit scores be used for? Traditional credit scores are used by banks or other lenders to approve loans, used by employers to screen candidates, and some other kind of approvals. Likewise, social credit scores can be used for similar purposes. Alibaba’s affiliate Ant Financial opened a strictly online bank called MyBank that serves small businesses and individuals. This online bank takes deposits the same way as Synchrony or AlyBank in the US do. But it also gives out unsecured loans (without any collateral) up to $850,000. That is a lot of money to lend without collateral (by the way, mortgages are secured loans collateralized by the house). Underlying the decision to lend or not to lend is social credit score, calculated based on huge amount of online transaction data.

Back to the US, which companies may have data that can generate a full or partial social credit score? I think Airbnb, Amazon, Facebook, Lyft, UBER and etc. all have huge amount of data that can be used for credit scoring. Due to the high regulatory cost (banks are highly regulated), it is not likely that any of them would want to become a bank. But they can take some of the businesses that banks always have been doing. For example, Amazon has Amazon Cash and variations of it in various countries such as the U.K. Also, UBER has recently offered UBER cash. These are banking businesses: they allow people to shop or ride without a credit or debit card as long as you load your account with cash.

What does aggregate mean?

In math and especially statistic, aggregate means to get some ideas on a set of numbers or measures.

For example, let’s say we are having lunch at the school cafeteria.  You may want to know some aggregated measures, such as:


Yes, this is still a Magic Math Mandarin blog–but to have tomorrow’s skills means a lot more than just knowing basic math.
API = plugin

This post is a quick note (updates are in progress).

Site that documents most APIs

hash function/ cryptography/ digital signiture

Hash function (散列函數):
Yes, this is still a Magic Math Mandarin blog–but to have tomorrow’s skills means a lot more than just knowing basic math.
A hash function maps arbitrary string of data fix length of bits.

The simplest (a bad one) is to use the ASCii representation of alphabet, sum up the numbers and take mod.   This creates a problem as “cat”, “act” and “tca” are going to be mapped to the same hash.  This problem is called “hash collision” 碰撞.


A CS lecture 马克十几年前教的课

It is amazing how much one can learn from this old video, recorded 2 years after Mark Zuckerburg left Harvard. Here is what I remember after listening 5 times:

1. Don’t follow what the big guys are doing. There is so much you can do on your own with technology (find your own problem and get to it)

Teaching long division (除法)

I was surprised to learn that my fourth grader daughter is learning long division exactly the same way as how I was taught: a highly mechanical process that is worse than doing dishes.

Now looking back, I learned a lot of math mechanically without putting much thought into what I was doing.  Perfecting the steps as if I was self-training to be a robot.

Tomorrow I am going to show why we did long division the way we did, and why there are many other ways.

Setting up Python after installing (or re-installing) Anaconda

Everyone of us (adult Python users at least) need to install or re-install Python or the one with Anaconda. Today I had to re-install everything related to Python due to trouble getting Tensor Flow started.   I primarily use Windows 10.  Below steps may serve some who are going through this.

What is HTML

To understand how website are built, one of the many things we need to know HTML.

Basic syntax of an HTML webpage. Every <tag> serves a block inside the webpage:
1. <!DOCTYPE html>: HTML documents must start with a type declaration.
2. The HTML document is contained between <html> and </html>.
3. The meta and script declaration of the HTML document is between <head> and </head>.
4. The visible part of the HTML document is between <body> and </body> tags.
5. Title headings are defined with the <h1> through <h6> tags.
6. Paragraphs are defined with the <p> tag.