You must also assess the strength of the evidence given your hypothesis

John Alen Paulos in a book review article titled, The Mathematics of Changing Your Mind.

At its core, Bayes’s theorem depends upon an ingenious turnabout: If you want to assess the strength of your hypothesis given the evidence, you must also assess the strength of the evidence given your hypothesis. In the face of uncertainty, a Bayesian asks three questions: How confident am I in the truth of my initial belief? On the assumption that my original belief is true, how confident am I that the new evidence is accurate? And whether or not my original belief is true, how confident am I that the new evidence is accurate?

[snip]

The theorem itself can be stated simply. Beginning with a provisional hypothesis about the world (there are, of course, no other kinds), we assign to it an initial probability called the prior probability or simply the prior. After actively collecting or happening upon some potentially relevant evidence, we use Bayes’s theorem to recalculate the probability of the hypothesis in light of the new evidence. This revised probability is called the posterior probability or simply the posterior. Specifically Bayes’s theorem states (trumpets sound here) that the posterior probability of a hypothesis is equal to the product of (a) the prior probability of the hypothesis and (b) the conditional probability of the evidence given the hypothesis, divided by (c) the probability of the new evidence.

Consider a concrete example. Assume that you’re presented with three coins, two of them fair and the other a counterfeit that always lands heads. If you randomly pick one of the three coins, the probability that it’s the counterfeit is 1 in 3. This is the prior probability of the hypothesis that the coin is counterfeit. Now after picking the coin, you flip it three times and observe that it lands heads each time. Seeing this new evidence that your chosen coin has landed heads three times in a row, you want to know the revised posterior probability that it is the counterfeit. The answer to this question, found using Bayes’s theorem (calculation mercifully omitted), is 4 in 5. You thus revise your probability estimate of the coin’s being counterfeit upward from 1 in 3 to 4 in 5.

I guess a variant on the adage that extraordinary claims require extraordinary proof.

A web of interconnected relationships is therapeutic enough to increase one’s odds

From Robin Dunbar How Many Friends Does One Person Need? Dunbar’s Number and Other Evolutionary Quirks, book review by Michele Pridmore-Brown. This is consistent with the posts from Deep Survival and the idea that a big portion of survival (and perhaps by extension, success) is motivation. The essay alludes to the Donner Party.

From an evolutionary point of view, what makes the story interesting is not the cannibalism — which, in the annals of anthropology, is relatively banal — but who survived and who did not. Of the 87 pioneers, only 46 came over the pass alive in February and March of the next year. Their story, then, represents a case study of what might be termed catastrophic natural selection. It turns out that, contrary to lay Darwinist expectations, it was not the virile young but those who were embedded in families who had the best odds of survival. The unattached young men, presumably fuller of vigor and capable of withstanding more physical hardship than the others, fared worst, worse even than the older folk and the children.

For Robin Dunbar, an evolutionary biologist cum anthropologist, stories such as this one highlight how human kin networks aid survival — and, therefore, why people may take great pains to manufacture kin, via godparents for instance, or marriage, or by obscuring or playing up paternity. He points to another earlier case of extreme selection: of the Mayflower colonists who set foot on the American mainland in 1620, 53 of 103 died in the first New England winter. Here, too, mortality was disproportionately high among the unattached. To take a less dramatic example, several retrospective studies suggest that children embedded in large families get sick less often than those embedded in much smaller kin networks. Dunbar’s conclusion is not just the obvious one — that families share resources, and thus have advantages over less connected, well-endowed individuals — but also that being at the center of a web of interconnected relationships is therapeutic enough to increase one’s odds of withstanding pestilential (and presumably existential) slings and arrows.

Let bookworms gnaw his entrails

A rather excellent curse as related in Dwight Garner's review of Stephen Greenblatt's The Swerve: How the World Became Modern.

Mr. Greenblatt reprints a curse that one monastery placed in its manuscripts upon those who neglect to return books. Some readers, I suspect, will wish to write it in their own books, perhaps even this evening. It begins: “For him that stealeth, or borroweth and returneth not, this book from its owner, let it change into a serpent in his hand and rend him. Let him be struck with palsy, and all his members blasted.” It goes on: “let bookworms gnaw his entrails”; “Let the flames of Hell consume him forever.” Amen, brother.

Noticing differences

From Learning and Memory Linked to Holding Objects in Hands by Susan Guibert. Proximity allows us to see differences. Distance allows us to see commonalities.

According to a study conducted by Associate Professor of Psychology James Brockmole and post-doctoral fellow Christopher Davoli, people holding objects they’re learning about process detail and notice differences among objects more effectively, while keeping the hands away from the objects help people notice similarities and consistencies among those things.

It translates more books in a single year than the entire Arab world has in the past thousand years

Why the Arabic World Turned Away from Science by Hillel Ofek. Measurement of things can be horribly abused but it can also significantly clarfiy situations and focus the mind.

There are roughly 1.6 billion Muslims in the world, but only two scientists from Muslim countries have won Nobel Prizes in science (one for physics in 1979, the other for chemistry in 1999). Forty-six Muslim countries combined contribute just 1 percent of the world’s scientific literature; Spain and India each contribute more of the world’s scientific literature than those countries taken together. In fact, although Spain is hardly an intellectual superpower, it translates more books in a single year than the entire Arab world has in the past thousand years. “Though there are talented scientists of Muslim origin working productively in the West,” Nobel laureate physicist Steven Weinberg has observed, “for forty years I have not seen a single paper by a physicist or astronomer working in a Muslim country that was worth reading.”

Comparative metrics on the Arab world tell the same story. Arabs comprise 5 percent of the world’s population, but publish just 1.1 percent of its books, according to the U.N.’s 2003 Arab Human Development Report. Between 1980 and 2000, Korea granted 16,328 patents, while nine Arab countries, including Egypt, Saudi Arabia, and the U.A.E., granted a combined total of only 370, many of them registered by foreigners. A study in 1989 found that in one year, the United States published 10,481 scientific papers that were frequently cited, while the entire Arab world published only four. This may sound like the punch line of a bad joke, but when Nature magazine published a sketch of science in the Arab world in 2002, its reporter identified just three scientific areas in which Islamic countries excel: desalination, falconry, and camel reproduction.

A slippery slope

It is important to always expand our understanding of the world and to recognize patterns out there. But once you have identified a pattern you then have to figure out whether anything should be done about it. Take as a for instance this research: Lower Turnover Rates, Higher Pay for Teachers Who Share Race with Principal, MU Study Shows by Nathan Hurst.

Key Findings

There is lower turnover in schools among teachers of the same race as the principal.

African American principals are more even handed in awarding supplemental salaries to teachers.

White principals are more even handed in awarding administrative support, encouragement, autonomy, intangible benefits and recognition.

African American teachers are more positive about working for a principal of the same race than are white teachers.

Minority teachers improve the educational experience of minority students

The studies authors conclude that "Our results illustrate that an important factor in maintaining the racial diversity of teachers is the diversity of the principals that supervise these teachers. We hope these findings could provide justification for policymakers to undertake programs targeted at increasing the flow of minority teachers into the principal pipeline."

Fair enough but it would also seem, to follow their thinking, that it would be logical to conclude that schools ought to be resegregated. Minority teachers improve the educational experience of minority students AND African American teachers are more positive about working for a principal of the same race than are white teachers. However, a logical answer isn't necessarily the right answer. The right answer depends on what are the goals, how are those goals prioritized and what are the trade-offs between goals.

Lots of questions about the rigor of the study, the sample size, etc. However, it would seem an object lesson about distinguishing the difference between recognizing patterns (is it real?) versus determining what is causing the patterns (why are they more positive?) versus the really critical decisions: Can we change it? Is it important to change it? Is it worth changing it?

Interesting data can be a slippery slope.

The correlation between growth and the creative class is by far the strongest

From The Metro-covery and the Limits of Growth Without Growth by Richard Florida. Talking about which cities are recovering and why - basically those cities with high productivity via a strong human capital base.

Let’s start with what’s not associated with regional economic growth. The economic growth of metros between 2007 and 2010 had little or no relationship to population size, density, levels of innovation, wages or places with warmer summers. It had only a weak relationship to high-tech industry and a weak negative association with housing prices.

Several factors clearly do stand out. Many commentators, from Peter Drucker and Daniel Bell to me have charted the shift from an industrial to a more knowledge-based, creative economy. The crisis appears to have accelerated this shift, as evidenced by the fact that the economic growth of metros has been most closely associated with the share of the workforce in knowledge, professional, and creative industries. The correlation between growth and the creative class is by far the strongest of any in our analysis (about 0.4). Education or human capital levels – measured as the share of adults with at least a college degree, another way of measuring knowledge-intensity – also plays a strong role (with a correlation of about 0.3). Despite the strong showings posted by some metros with traditional manufacturing economies, economic growth was much less likely to occur in metros where the working class makes up a greater share of the workforce. Metro GDP is negatively associated with the share of working class jobs in a metro (with a correlation of -0.2).

You Americans never made simple stupid decisions

The Qwikster and the Dead by Megan McArdle.

The whole thing reminds me of a quote I once heard from some foreign diplomat about the US. "You Americans never made simple stupid decisions. You only make complicated stupid moves that make the rest of us wonder if we aren't missing something."

Viewing things as worse when they are getting better

As we move closer to the goal of obviating something we dislike, there is a tendency to invest more in proving how bad the remaining problem is. This is particularly true when we never paid close attention to how to measure the goal in the first place or when we never clarified priorities and trade-offs.

There is a tendency to refocus from first-order impacts to second-order impacts and to make the case that the second-order has a greater impact than the first order. In 1950, there were many forms of first order institutionalized racism, de facto and de jure. Today there is no de jure racism and very little first-order (overt) de facto racism. The focus has shifted from the obvious first-order issues to second-order issues of unconscious racism, racism manifested by unintended systemic design etc. It is indisputable that first order racism was materially deleterious to all concerned in 1950. We tend to treat second-order racism, much less measurable and to some extent therefore much less real, as if it were as consequential as first-order racism. It is not. We have made progress and yet in the noise of our discourse it would seem we have not.

Part of this is perhaps owing to a shift from systemic driven events to events driven by randomness. We have control over systemic events, we do not have control over random events (though we can mitigate them). Of the top twenty systemic events by loss of life in the US (building fires, shipwrecks, explosions, mining disasters, etc.) none of them have happened in the past fifty years. Even among the randomly driven events (tornadoes, floods, forest fires, hurricanes, blizzards, earthquakes, etc.), only three of the largest events by loss of life have occurred in the past fifty years.

Virtually all desirable human goals (such as longevity, health, wealth, education levels, etc.) have dramatically improved in the past fifty years to levels never seen before.

At the same time, virtually all negative outcomes (such as infant mortality, crime, environmental degradation, wars, etc.) have also dramatically declined.

Logically, one would conclude that we are living in a privileged and halcyon period of the human species (as I believe we are) but there is little sense of that in our common forms of shared communication (songs, movies, news reports, popular novels, etc.). In fact the reverse. Things are always painted as getting worse. Why?

It is good to always be striving to improve things but it is also important to maintain a sense of perspective and reality. The more we exaggerate the consequences of second-order issues, the less likely we are to focus on other first-order issues we have not yet tackled and which might have greater consequence. In other words is this simply a function of social inertia? We rally around some set of issues that need resolving. After twenty years we make great progress but instead of then reexamining what are now the top list of things that need fixing, we continue to focus everything on the remaining agenda of the original problems despite the declining return on the effort.

Mothers co-read books communicated significantly more with their children

TV found to have negative impact on parent-child communication and literacy from e!ScienceNews.

The results demonstrated that who mothers co-read books communicated significantly more with their children than mothers watching TV. The amount of communication involved in reading was not significantly higher than playing with toys. However, the quality of maternal responsiveness was higher in books than toys.