Are economics and finance “lost in math”?

Is physics “lost in math”?

In a provocative new book, Lost in Math: How Beauty Leads Physics Astray, quantum physicist Sabine Hossenfelder argues that the scientific world in general, and the field of physics in particular, has repeatedly clung to notions that have been rejected by experimental evidence, or has pursued theories far beyond what can be tested by experimentation, mainly because these theories and the mathematics behind them were judged “too beautiful not to be true.” Examples cited by Hossenfelder include:

Supersymmetry. Supersymmetry, the notion that each particle has a “superpartner,” was originally proposed in the 1970s, and

Continue reading Are economics and finance “lost in math”?

New video explains the danger of selection bias in finance

A new video has been produced by the Mathematicians Against Fraudulent Financial and Investment Advice (MAFFIA) group. It explains, in simple terms, how many of the financial strategies and funds available today are based on a statistically dubious foundation, typically rooted in selection bias effects, because the finance world, unlike other fields such as the pharmaceutical industry, has not yet been forced to adopt the necessary rigorous statistical methodology to prevent such problems.

As a result, we often see a “vicious cycle”:

Academic researchers publish a paper describing a new investment strategy, but fail to disclose the fact that they

Continue reading New video explains the danger of selection bias in finance

Bailey and Lopez de Prado on the crisis of pseudoscience in finance

In a 25 May 2018 Forbes article, Brett Steenbarger interviews David H. Bailey and Marcos Lopez de Prado on the growing crisis of pseudoscience in finance. We do not mince words. Hopefully it will get noticed and have an impact.

Here is an excerpt:

Imagine that a pharmaceutical company develops 1000 drugs and tests these on 1000 groups of volunteer patients. When a few dozen of the tests prove “significant” at the .05 level of chance, those medications are marketed as proven remedies. Believing the “scientific tests”, patients flock to the new wonder drugs, only to find that their conditions

Continue reading Bailey and Lopez de Prado on the crisis of pseudoscience in finance

Economics, finance and pseudoscience

Beware snake oil salesmen!


Bloomberg columnist Mohamed El-Erian recently lamented that the discipline of economics “is divorced from real-world relevance and has lost credibility.” Among the problems he mentions currently afflicting the field are the following:

The proliferation of simplifying assumptions that lead to an “overreliance on excessively abstract estimation techniques and approaches.” Insufficient consideration of the possibility that financial dislocations can disrupt the economy. Poor and grudging adoption of important insights from behavioral science and other disciplines. An oversimplification of uncertainty. An overemphasis of equilibrium conditions and mean reversion, and an underemphasis on structural changes and tipping

Continue reading Economics, finance and pseudoscience

The most important plot in finance

In this post we look at the one plot that proves that technical analysis is useless.

Technical analysis and horoscopes

As volatility has returned in recent months, investors have sought advice from asset managers and other investment professionals. In many instances, such advice includes technical analysis (TA). Even many highly respected investment firms and financial news sources promote TA:

Charles Schwab represents TA as an indispensable tool for active traders (examples: here and here). Merrill Lynch offers a Market Analysis Technical Handbook. Some Bank of America / Merrill Lynch analysts utilize technical analysis: here. Fidelity considers TA an advanced technique

Continue reading The most important plot in finance

Advances in Financial Machine Learning


Two of the most talked-about topics in modern finance are machine learning and quantitative finance. Both of these are addressed in a new book, written by noted financial scholar Marcos Lopez de Prado, entitled Advances in Financial Machine Learning.

In this book, Lopez de Prado strikes a well-aimed karate chop at the naive and often statistically overfit techniques that are so prevalent in the financial world today. But Lopez de Prado does more than just expose the mathematical and statistical sins of the field. Instead, he presents a technically sound roadmap for those who want to do state-of-the-art

Continue reading Advances in Financial Machine Learning

Does indexing threaten the market?


Index investing has grown significantly over the past 30 years. Back in 1990, few were even aware of the option for indexing, and options were limited mostly to a handful of conventional mutual funds tracking the U.S. S&P 500 index. In 1993, Boston’s State Street Global Advisors launched the first S&P 500 index-tracking exchanged traded fund (ETF), with ticker SPY. Today this ETF controls over USD$300 billion in assets. Thousands of other index-tracking mutual funds and ETFs, tracking numerous different indices, in numerous different world markets and regions, are now in operation; in the U.S. alone, there were 1716

Continue reading Does indexing threaten the market?

Can mutual fund investors beat the market?

FTSE 100 index


Many individual investors employ mutual funds as an alternative to direct ownership of stocks or bonds.

Indeed, mutual funds have some advantages:

Diversity: Even a single fund can encapsulate a large sector of the market. Peace of mind: One is less likely to stress out about sudden bad news regarding a particular firm if one owns shares in it only indirectly as part of a large mutual fund’s portfolio. Management fees: Several leading index mutual funds have even lower management fees than corresponding exchange-traded funds (ETFs). And as a class, mutual funds have significantly lower

Continue reading Can mutual fund investors beat the market?

Can the January effect be exploited in the market?

Hoarfrost: Courtesy Wikimedia


The “January effect,” in common with the “Halloween indicator” and “sell in May and go away”, is a catchy, get-rich-quick investment idea adored by financial commentators because it is so easy to explain to unsophisticated readers. It rests on the claim that the U.S. stock market performs better in January, compared to the other months in the year.

Unfortunately, financial reports promoting the “January effect” are often vague and confusing. One recent example is here, which, like others in this genre, lacks a specific actionable investment strategy. In fact, this particular report does not even

Continue reading Can the January effect be exploited in the market?

Overview of the Mathematical Investor

This site was created out of growing concern with the usage of less-than-fully rigorous mathematical and statistical methodologies in the financial/investment world. One example is the increasing prevalence of backtest overfitting, due in part to the ease of generating large numbers of model variations (more than statistically justified) using modern computer technology. Indeed, such statistical errors are likely the primary reason that investment strategies which look good on paper often fall flat in practice.

We are also concerned with the proliferation of quasi-mathematical investment advice and financial columns in the past few years, which appear to be based on sophisticated

Continue reading Overview of the Mathematical Investor