Warning: include_once(/home/nullvoid/blog.mikezhang.com/wp-content/plugins/wordpress-support/wordpress-support.php): failed to open stream: Permission denied in /home/nullvoid/blog.mikezhang.com/wp-settings.php on line 217

Warning: include_once(): Failed opening '/home/nullvoid/blog.mikezhang.com/wp-content/plugins/wordpress-support/wordpress-support.php' for inclusion (include_path='.:/usr/local/lib/php:/usr/local/php5/lib/pear') in /home/nullvoid/blog.mikezhang.com/wp-settings.php on line 217
NullVoid » Random Thoughts NullVoid » Random Thoughts

Random Thoughts

Best Birthday Gift

Friday, June 3rd, 2011 -- By ET

It was my birthday on June 1 (yes, the children’s day, that’s why I don’t get old).

My friend John was visiting, he was bored so dragged me to watch the Horse Race in Happy Valley.

The point is really not watching horse. We were busy checking the statistics of the horses and played a few hands. I typically don’t do gambling because I always believe it is a form of “stupidity tax”. This time, however, I played. Of course, we lost.

Just before we were ready to leave, I got the email (can’t imagine the days without iphone). It was the acceptance letter of my paper by Management Science.

So I guess this is the best birthday gift ever. I started working on that paper in 2003, then presented it in 2005. Presented it as my job market paper around the world (literally), and it won me quite a number of great job offers. However, it was such a long journey to publish it. It stayed at one particular journal for 18 months before I got two very irresponsible reviews.

Probably we were one of the first to write on the topic, when we first submitted it in 2006/2007 the reviewers could hardly understand what we were talking about. After several years of extensive study by many other colleagues, finally the value of the paper gets recognized. When we submitted it to MS in 2010, one of the reviewers said:”This is a very timely study to look at dynamic features of keyword auctions, while the majority of the literature still relies on static models.”

Some friends asked me if the reviewers knew the “inside information” of my birthday. I guess not, even if they do, it would be hard to coordinate so that the editors can send out the notification exactly on that day.

For the record, my dear reviewers, please do not wait to surprise me only on my birthdays. Surprise me now! Surprise me any time!

Thoughts on Survival of the Fittest

Wednesday, March 30th, 2011 -- By ET

The theory of the survival of the fittest suggests that species adapt to the environment to survive. For example, insects may develop colorful patterns on their wings to scare off potential predators. The biological foundation for such changes and adaptations can be gene mutation.

Then a question arises: suppose mutation can trigger some effects so that an animal suddenly becomes poisonous. Why the poisonous feature cannot stay like the colorful pattern on insects? Fortunately not, if yes, then many things we see today will be poisonous!

One explanation is that the colorful patterns are salient features, so they can immediately be effective to protect the insects. In the long run, this feature can be passed onto future generations. The poisonous feature is not salient. So a wolf will continue to eat that poisonous rabbit and there is no chance for the poor rabbit to pass on this great feature.

In a sense, these poisonous rabbits are like experience goods. Before you consume them, there is no way for you to know their quality. You only learn about their quality after you eat them, but then it is often too late for you to regret. It is a blessing for us that there is no review systems (e.g., those similar to Yahoo movies, Yelp, etc.) in nature. If yes, then the poisonous rabbits can pass on the feature and today we will have to face many more poisonous animals.

My Social Graph on Facebook

Sunday, February 13th, 2011 -- By ET


Saturday, November 20th, 2010 -- By ET

以下轉載自 新浪中醫頻道:
如今不孕不育在我國已經成為「通病」。 近五年來,中國每年都有上百萬對的夫妻因不孕不育而去醫院就診。







Friday, August 27th, 2010 -- By ET

I came across a senior professor in Statistics in the hall way. He noticed that I moved my office.

I told him that the new office has a window, and my research productivity increased by 5 times.

He then said:”Wonderful, they should have installed 2 windows for you.”


Traits of Successful Business Executives

Friday, August 13th, 2010 -- By ET

I’m doing some literature review for a paper of mine. I came across the following paper:

The Business Executive: The Psychodynamics of a Social Role

By: William E. Henry

The American Journal of Sociology, Vol. 54, No. 4, Industrial Sociology (Jan., 1949), pp. 286-291.


It was written in 1949, and talks about the common characteristics of successful business executives. Typically I do not find these descriptive papers useful, but it is interesting to see how people in 1949 perceive what executives should do to be successful.

The paper listed the following personality patterns that are common for success:

    Achievement Desires
    Mobility Drive
    Idea of Authority
    Ability to Organize Unstructured Situations
    Strong Self-Structure
    Apprehension and the Fear of Failure
    Activity and Aggression
    Strong Reality Orientation
    Different Interpersonal Relations with respect to Superiors and Subordinates
    Broken Tie with his own Parents
    Dependency Feelings and Concentration Upon Self

That was a long list, if you check these on people we know, say Steven Jobs, you would probably be amazed how accurate these items can “predict” his success. I’m constantly suspicious of this type of work because they obviously miss the sample of failed cases. It could be the case that people who share these traits fail more, but due to the sample selection problem, we cannot observe them. What if some other factors are driving the success of these people, and they just learned to behave in this way (i.e., behaving in this way does not produce success.)?

This brings back to the argument of my paper: when people assume social roles, they behave according to the perceived traits of these roles. In many situations, the list of characteristics is a result of being successful, not a source of it.


Friday, August 6th, 2010 -- By ET

大陆是什么都不能做,包括法律允许 的。

Marshmallow Experiment – A Video.

Thursday, August 5th, 2010 -- By ET

I wrote about Marshmallow experiment a while ago.

Now here is a video:

I wonder how this test can pass the human-subject approval. For sure, these kids (except the little girl who ate it immediately) will be harmed and haunted for the life…

Unlocked iPhone 4 is Cheapest in HK

Tuesday, August 3rd, 2010 -- By ET

I guess there is no point of not buying it now.

This, however, is related to another psychological bias: people compare options in terms of gains/losses with respect to a reference point, not with respect to wealth. I’m happy to buy the iphone because I learned it is a good bargain in HK, not because I believed it delivers that much utility to me (although probably it will).

I think this figure should be on every HK iphone seller’s ad, I bet the effectiveness would give the highest ROI.

Market Efficiency Test

Monday, August 2nd, 2010 -- By ET

I’m here in Singapore for a 2-week summer institute of behavioral economics/finance. Vince Crawford, Matthew Rabin, Ted O’Donoghue and Terry Odean are the speakers.

Some keywords that surface frequently in the discussions are “bounded rationality”, “market efficiency”, “human bias”, “anomalies” etc.

This reminds me of a joke:
An economics professor and a student were strolling through the campus.
“Look,” the student cried, “there’s a $100 bill on the ground!”
“No, you are mistaken,” the professor replied. “That cannot be. If there were actually a $100 bill, someone would have picked it up.”

That is probably the most famous joke about economists. The professor is certainly a believer of Market Efficiency.

Next watch the video:


What makes all passers-by to ignore the wallet? Are lay-people suddenly believers of market efficiency?

You are visitor number several since September 1, 2001

Copyright Xiaoquan (Michael) Zhang, 2004-2020. All rights reserved.
All trademarks property of their owners.