A CS Professor's blog

How does one estimate the accessibility of a text? What leads to labels such as "This is at the 9th grade reading level"?

Apparently one big factor is the distribution of the number of syllables in the words. Another factor is the length of sentences. Here's a typical formula:
You can use a formula to calculate Flesch-Kincaid reading level on your own. This is a good tool to determine whether a book is going to challenge you.
1. Select a few paragraphs to use as your base.
2. Calculate the average number of words per sentence. Multiply the result by 0.39
3. Calculate the average number of syllables in words (count and divide). Multiply the result by 11.8
4. Add the two results together
5. Subtract 15.59
More on http://www.micropowerandlight.com/rd.html

I have reservations about these tools, at least as applied to material for adults. A text is difficult if it contains many unknown words, of course. One of the tools proposed maintains a database of words; perhaps they are ranked according to frequency in the English language, and one reasonable measure of difficulty would be the frequent occurrence of rare words.

But a text is also difficult if its structure is convoluted. Doing a grammatical analysis and parenthesizing relative clauses, one could compute the levels of nested parentheses, thus measuring the number of partial sentences that the reader must simultaneously keep in mind as he or she is reading. That should be an important factor in readability.

Examining vocabulary is similar to examining the number of notations that the reader of a scientific paper must familiarize himself with and must memorize as he is reading. Studying the nested structure is similar to studying the number of assumptions that the reader must keep in mind while processing a proof ("This is a proof by contradiction, with a case-by-case analysis, and we are in the "else" part of the "if" statement of case 2"...). Shouldn't there be a rigorous way to measure and analyze those parameters in readability?

Avi Wigderson: "-Why tolerate errors [in outputs of randomized algorithms]?
-We tolerate uncertainty in life."

Ehud Friedgut: "You have to realize that, when people say: "This is very tiny", sometimes they mean 1/100 and sometimes they mean one over ten billion."

Neither realized it at the time, but they could have been commenting on the Fukushima nuclear plant accident!

The people who are here at the Newton Institute (Cambridge, UK) this week are largely the same ones who were in Paris last week, or at Dagstuhl earlier, or in Jerusalem last year. Why do we go from place to place like a flock of migratory birds? What instinct prevents us from settling down anywhere in particular?

Here is what Christopher Lasch writes in his book "The revolt of the elites":
"Ambitious people understand that a migratory way of life is the price of getting ahead. It is a price they gladly pay, since they associate the idea of home with intrusive relatives and neighbors, small-minded gossip, and hidebound conventions. [...] Those who covet membership in the new aristocracy of brains tend to congregate on the coasts, turning their back on the heartland and cultivating ties with the international market [...] Patriotism, certainly, does not rank very high in their hierarchy of virtues. "Multiculturalism", on the other hand, suits them to perfection, conjuring up the agreeable image of a global bazaar in which exotic cuisines, exotic styles of dress, exotic music, exotic tribal customs can be savored indiscriminately, with no questions asked and no commitments required. The new elites are at home in transit, en route to a high-level conference, to the grand opening of a new franchise, to an international film festival, or to an undiscovered resort. Theirs is essentially a tourist's view of the world -- not a perspective likely to encourage a passionate devotion to democracy."
"Their loyalties -- if the term is not itself anachronistic in this context -- are international rather than regional, national, or local. They have more in common with their counterparts in Brussels or Hong Kong than with the masses of Americans not yet plugged into the network of global communication."

Ouch. Thankfully, I cannot possibly fit that description since I am staying in a dorm with a shared bath!

During my visit to Paris my two offices and my studio were all essentially on the same block, that I got to know by heart.

By the bakery on rue Gay-Lussac, there is a beggar, not always the same one. One day there was a woman and child, who I noticed looked at the chocolate bun that I had bought for breakfast. I gave the child half of my bun, whereupon the adult immediately said: "She is thirsty, too." I answered: "I can't give her that" and went on my way, annoyed for some obscure reason.

By the sea and water institute, there sometimes is a man begging and looking sad. After emptying the tiny fridge in my studio and checking out, as I walked by him with my bag of leftover groceries, his eye caught mine and I was compelled to offer him some of my extra food. But he refused my offer of a box of microwavable lentils and bacon dish: "I have no way to reheat it", he explained. I looked again in my bag, but there was nothing edible without cooking. "Sorry, I don't have anything else", I said regretfully. "It's all right, never mind. Have a nice day!", he answered gracefully. I continued on my way, wondering about the one thing that I could have given him but chose not to take out of the bag and offer him: a bottle of wine...

On rue Pierre et Marie Curie, there are often traces of a presence on the street: empty beer bottles, a sleeping bag drying on a railing, and sometimes an indistinct human form buried in layers of cloth. When I stayed late in the office, once or twice I heard loud drunken noises coming from the street.

At the corner of rue d'Ulm, there is a phone booth that was inhabited last January, but that is currently available. On the other hand, a woman seems to be spending many of her days sitting on a heat grate on the sidewalk. Late one night, I saw a shape in a sleeping bag, set up in the middle of the street, on the piece of pavement off limits to traffic that marked the middle of the intersection! Was it her? Was that her way of setting up some boundaries?

Further down rue d'Ulm, there is a university whose main entrance cuts off the first floor of the building diagonally, providing a shelter. A beggar is set up there. Sometimes he is sleeping. Other times, some large pieces of cardboard are set out and dozens of books are on display, as an improvised streetcorner bookstore. I wish I had looked at it more closely.

Closer to the RER, by the side entrance of the church of St Jacques d Haut Pas, there is a beggar, usually but not always an older woman. One day she was selling daffodils and I bought a bunch, happy with that creative way to generate an income. But she was indifferent to my presence and never raised her eyes to my face. She is only there during the day: perhaps she has a home to go back to at night.

The main entrance of that church also has occasional beggars, two men, but they're not regulars. Maybe they're only there at night and to ask for charity at Mass time.

The beggars in Paris are diverse. Men and women, young and old, with dog or child. I have seen an old woman reading a prayer book, oblivious to her environment. I have seen a young woman, her hair carefully covered with a scarf, in a silent kneeling posture, full of dignity. Her body is there, but her mind seems absent. According to statistics 17 percent of homeless people in Paris are women.

I often wonder what kind of beggar I would be.

Avi Wigderson taught a mini-course on expanders in Paris last week. I spent some time there learning about expanders, and some time learning about teaching.

When I present an algorithm or proof in a talk, in order to convey the main ideas, I sometimes ignore side concerns, which sometimes makes me take liberties with correctness stricto sensu. Avi takes that approach and carries it to an extreme: when briefly presenting a research direction, he may choose to briefly outline the prettiest algorithm, while briefly citing only the most important paper on the subject, even if there is a mismatch between the result outlined and the paper cited! I would not dare do that (at least not on purpose), for fear of catching hell from authors. But it is morally doing the right thing: giving a pointer to the one paper interested students ought to look at, while attracting them with hints of the most elegant results.

It's sacrificing accuracy in the details, so as to better get the essential ideas across. In fact, it's also sacrificing some accuracy to beauty. It's an anti-Pharisee stance: Pharisees, I am told, were so obsessed with rules and with following every detail of every ritual in exactly the right way, that those regulations obscured the overall purpose of their religious practice.