Aug

13

A case study in multiple comparisons and a warning against using cart for market prediction:

"Exercising for 90 Minutes Or More Could Make Mental Health Worse, Study Suggests"
by Sarah Knapton, Science Editor

Steve Ellison writes: 

A statement by Mark Hulbert in Sunday's Wall Street Journal raised my suspicions. He said that the percentage of household financial assets invested in stocks had an R-squared of 61% since 1954 in forecasting the net change of the S&P 500 over the next 10 years.

There have only been 6 non-overlapping 10-year periods since 1954. I have not gotten around to getting the data for household financial assets, but how could any factor possibly have an R-squared of 61% with any significance after 6 observations?

I will grant that the indicator makes some intuitive sense from the perspectives of "copper[ing] the public play" and waiting to buy until the old men are hobbling on canes, but I question the statistics.

Link and relevant excerpt below:

The most accurate of the indicators I studied was created by the anonymous author of the blog Philosophical Economics. It is now as bearish as it was right before the 2008 financial crisis, projecting an inflation-adjusted S&P 500 total return of just 0.8 percentage point above inflation. Ten-year Treasurys can promise you that return with far less risk.
Bubble flashbacks
The only other time it was more bearish (during the period since 1951 for which data are available) was at the top of the internet-stock bubble.
The blog’s indicator is based on the percentage of household financial assets—stocks, bonds and cash—that is allocated to stocks. This proportion tends to be highest at market tops and lowest at market bottoms.
According to data collected by Ned Davis Research from the Federal Reserve, this percentage currently looks to be at 56.3%, more than 10 percentage points higher than its historical average of 45.3%. At the top of the bull market in 2007, it stood at 56.8%.
Ned Davis, the eponymous founder of Ned Davis Research, calls the indicator’s record “remarkable.” I can confirm that its record is superior to seven other well-known valuation indicators analyzed by my firm, Hulbert Ratings.
To figure out how accurate an indicator has been, we calculated a statistic known as the R-squared, which ranges from 0% to 100% and measures the degree to which one data series explains or predicts another.
In this case, zero means that the indicator has no meaningful ability to predict the stock market’s returns after inflation over the next 10 years. On the other hand, a reading of 100% would mean that the indicator is a perfect predictor.
Since 1954, according to our analysis, the Philosophical Economics indicator had an R-squared of 61%. In the messy world of stock-market prognostication, that is statistically significant. Our analysis begins in that year because that is the earliest date for which data are available for all of the other indicators that we studied.

Jared Albert writes: 

As I understand the statement, the R**2 is generated from the correlation between the end of one ten year period and the end of the other.

Is this a fair model:
1) Use the annual returns for the SP500 for the period 1954-2014 broken in the 6 decade buckets.
2) Use the standard deviation of returns for each of those 10 years periods (STD calculated on only 10 yearly values for simplicity).
3) Generate a random return value from a normal distribution for the end year of each period
4) repeat the above for cash and bonds
5) create the portfolio ratio of stocks:bonds:cash
6) calculate the r**2 value between every 10 year period for stocks
7) do this 1000 times and calculate the summary stats for the R**2

Is this the way to build the model? I may do this later, if I can quickly find the cash and bond return. Thank you,

May

16

 "I understand your here to collect your share?" said the Keeper.

"My share of the taxes, yes," said the Visitor, "Piketty sent me."

"Are you sure you want to tax capital? I mean, really sure?" said the Keeper.

"It's only fair," said the Visitor.

"Well, to register and receive you must put on this headset," said the Keeper, handing over a kind of halo object, "it will read your Identity Number, calculate your distribution and begin making a fair deposit."

"Perfect!" said the Visitor, and popped the contraption onto his head. The Keeper stared at him directly, a thin smile on his lips.

The Visitor pressed the power button on the halo. "Aaaah! No, please. What." The Visitor spasmed wildly. "Aaargh! Oh my God! Please, please." The Visitor's flight reflex kicked in, his muscles began to shake violently, bringing him to his knees. The tension in his bladder collapsed and piss soaked his pants. The Visitor writhed on the floor, "MAKE IT STOP! What is this?!"

The Keeper quickly pulled a handset from his pocket and clicked the interrupt. Nobody so far had completed the deposit in full. The Visitor fell to the floor, exhausted. With his eyes blood shot, watering, the Visitor cried out, "how dare you, what was that torture? You fiend! This is criminal."

"You asked for your share," said the Keeper, "and your bank account is in credit now. Your share of the capital taxes have been delivered, proportionately."

"Are you some kind of SICKO?" screamed the Visitor.

"No. You see, you asked for your fair share. We decided in transferring capital taxes, we should also make an additional deposit to keep it balanced. We gave you a concentrated dose of every sleepless night, strained relationship, cheating business partner, every lie heard, every deal that didn't close, every set-back, every busted asset, every temptation skirted, idea stolen, regulatory intervention, bankrupt supplier, every loss adjusted insurance policy, every giant competitor… all of it. And there's much, much more. Should I complete the deposit?" asked the Keeper.

The Visitor staggered up to his feet, raised his eyes to the Keeper and paused to speak. But nothing came. Instead, he ran straight for the door.

Jared Albert writes:

I think the basic problem with Piketty style wealth redistribution is that everyone wants to read poetry, while no one wants to take out the trash.

That effort is often necessary for wealth, doesn't answer his basic point that in a fairer world we'd help those who strove and failed as well.

Victor Niederhoffer writes: 

Yes, Mr. Albert has encapped the idea that has the world in its grip. When I played ball, I always wished that my opponents would share their points when they beat me. There should have been a law. 

Jared Albert replies: 

A lot of effort has gone down dead ends in battery technology. Those efforts uncovered what doesn't work, and provided methods that may end up pushing some methods forward. Those failures benefit all of us.

According to an ideal Piketty model, the losers should be compensated in some form by winners as they helped move the sum of the effort forward.

I don't know for sure obviously, but I doubt you can find a nobel laureate who doesn't feel that they stood on the shoulders of others.

My point is that in general people are dis-incetized to try any of the routes if their reward has nothing to do with effort.

Stefan Jovanovich writes: 

In a fairer world we do help those who strive and fail; that is how successful teams (right now and for the past 5 seasons under Bruce Bochy, the SF Giants) and families (the anonymous R-Man's to take one of many examples from the List) and enterprises all work. As with most Leftist ideas Piketty has a valid complaint; as with all ideas based on the sacrifice of individual freedoms for collective good his Marxist solution is catastrophically bad. Some people do want to take out the trash rather than let it pile up, but no one does it for very long for the sake of strangers without getting paid in money that he or she gets to keep and spend. That is why inventive and naturally poetic people in Cuba live in a world of uncollected trash and free medical care where the patients bring the medicines to the doctors. But it is fair — everyone lives under the same collective incentive to read official poetry.
 

Sep

26

My grandfather Martin was a language genius who spoke about 30 languages. He was court interpreter at the start by faking that he knew Yiddish and Russian when he was waiting around bankruptcy court for real estate to buy without cash. He needed the 5$ he got from the gigue to pay for ice skating lessons for Artie. Artie on his 40th birthday gave himself a special present. He bought himself his first tennis lesson that he could afford. A $3 lesson with Phil Rubell. The grandfather was very acerbic and was chagrined that the court clerks got double the salary of the interpreters. So at 68 he took the court clerks test, and got the second highest mark. In any case, at a time like this, he liked to say, "in their quiet way, stocks have arabesqued down 30 big points (S&P), and I think the path of least resistance is back above the round number".

And on a day like this Birdie his wife, who he proposed to the first time she bent over and took stenography for him, "I have to know now or I'll never ask you again", (her job was silent movie pianist, and that helped her in the stenography), liked to say "Martie, I see the market is way up— you look mad. I hope you weren't, how do you say it —- 'short'". 

Jared Albert writes: 

I imagine that the readers of this site could put together quite a few wonderful comments that significant other's make about one's troubles trading.

My wife told me to not be an idiot and just double my size as I was already sitting there, when I suggested that I would split the account and teach her to daytrade.

She also likes to assure me that there is strong support at zero when she see that the market is down.
  

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