This is called an "index", or a "proxy". This is because word length is correlated with word frequency, and word frequency is correlated with word difficulty. "Longer words are, "on average", harder than short words".
Word length is measured by counting the letters in each word, or by counting syllables. Since most syllables have one vowel, some computer programs count vowels per average word. A few tests measure the percentage of words on a list; the list is based on the known frequency of words in a language.
Sentence difficulty is usually measured by sentence length. This again is an index, because longer sentences are, on average, harder than short sentences. Computers count the number of words between full stops, but this is a second-best method. Humans can judge whether a semi-colon or colon should count as the end of a sentence for testing purposes.
Since both factors may vary independently of each other, the best prediction is gained by devising a formula with makes use of both indices. What this means is that a single score is produced for a text, and that score is looked up on a table or graph. That tells you how difficult the text is in terms of either a) an American school grade level, or b) an artificial scale of 0% to 100%. Either way is effective. What really makes a difference is:
It is possible to get a good prediction by getting a group of subjects to read through a passage, followed by multiple-choice questions. Even better is a method called cloze, where subjects fill in blanks on a text they have not seen before. The percentage of correctly completed blanks is an outstandingly good predictor of text difficulty.
Naturally, this kind of direct measure requires subjects and a skilled experimenter. It also requires the prior preparation of texts suitable for the chosen sample of subjects. The method is therefore too expensive for widespread use.
A person can perform readability tests himself by counting and doing some math, or by using word-processing software.
Wikipedia Signposts 2015-06-24 surveyed recent studies of web information on medical topics, including articles in English wiki.
Their summary was:
That shows these articles, and presumably many other medical articles on English wiki, are written in prose far too difficult for the average member of the public.
Theatre
Theatre (British English and also American English), or Theater (mostly American English), has several meanings.
The word comes originally from the Greek "Theatron", meaning roughly, 'a place to behold'. In American English, the word 'theater' can mean either a place where films are shown (this is also called a cinema) or a place where live stage plays are performed. In British English, 'theatre' means a place where live plays are performed. Some people, both English and American, use the spelling 'theatre' to mean a place where live plays are performed, and the spelling 'theater' to mean a cinema.
'Theatre' can also mean the business of putting on plays. An actor might say "I am in the theatre business", or a writer might say "I write for the theatre", meaning that they write plays, rather than writing for movies or television shows.
The first people we know created plays were the Ancient Greeks, about the year 500 B.C. They divided plays into two kinds: tragedy and comedy. This division is still used today. The best known Ancient Greek writers of plays are Aeschylus, Sophocles, Euripides and Aristophanes. Some of their plays survived, and are still performed today.
These ancient Greek plays were performed outdoors in large amphitheatres, so that many people could see them. There were contests among the playwrights (people who write plays are called playwrights) and the winner would get a prize.
The Greeks had many brilliant ideas. They used mechanical devices like trap doors and the "machina": a crane for winching gods on and off the stage (hence 'Deus ex machina'). They had a "Greek chorus" that offered information to help the audience follow the performance. The chorus comments on themes, and shows how an audience might react to the drama. The players wore masks. Illustrations on vases show helmet-like masks, covering the entire face and head, with holes for the eyes and a small aperture for the mouth, plus a wig. The mask was to ‘melt’ into the face and allow the actor to vanish into the role. Therefore, onlookers did not think about the actor, but thought about the character.
In the Middle Ages, the Catholic Church began to use theatre as a way of telling the stories from the Bible to people who did not know how to read. They wrote Mystery Plays, where each part of the Bible story would be a play put on by a different group of people. They wrote "miracle plays" which were about the lives of the saints. They wrote "morality plays" which taught the audiences how to live a good Christian life.
In the 1500s, groups of actors toured around Italy performing comic plays to entertain townspeople. These plays were called Commedia dell'arte, and different stories would be created around the same group of characters. Often the spoken lines would be made up by the actors for each performance.
Other kinds of plays called Neoclassical Dramas and Neoclassical Comedies were also popular in Italy and in France at this time. These plays were written to copy the style of the plays from Ancient Greece and Rome.
At the end of the sixteenth century (before 1600), the traveling actors began to perform in fixed theatre buildings. This was the period when William Shakespeare wrote. He lived from 1564 to 1616. At that time, in England, women were not allowed to perform, so male actors would play female characters.
His theatre was in London, England. It was called The Globe Theatre. It was an outdoor theatre and plays were performed in the daytime for large audiences. His plays were very popular and many are still performed today. Many people believe Shakespeare was one of the best playwrights (a writer of plays).
Plays including Shakespeare's were banned during the Protectorate'. After that, many more were written and acted.
After World War II, playwrights in Europe and the United States began doing plays in a new style called "Theatre of the Absurd." After seeing the horrors of war, these playwrights felt that all their old values had been destroyed. Playwrights such as Samuel Beckett, Eugène Ionesco, Harold Pinter, and Jean Genet wrote plays that are considered to be "Theatre of the Absurd."
The "Theatre of the Absurd" plays have some of the same ideas that are found in the philosophy (a way of thinking) called existentialism. Existentialism is very different from many other "philosophies". Most religions and philosopies say that human life has a meaning (or a purpose). The philosophy of existentialism is that human life does not have a meaning (or a purpose). When something has no meaning, it is "absurd". (absurd means means silly and meaningless.)
The plays written in this style make people think about questions like "what is it like to be a person in the world?" and "what does it mean for a person to be free?" They are often filled with sad emotions, such as worry, fear, and thoughts about death.
Theatre breaks are a form of short holiday, based around viewing a theatrical convention show. Theatre breaks tend to include a nights hotel accommodation included in the price.
Test
A test is a way of checking something to see if it is true, or false, or if it is edible or not. If something can be tested, or finishes the tests correctly, it is testable. The "Concise Oxford English Dictionary" defines a test as: "a procedure intended to establish the quality, performance, or reliability of something".
A test is different from an experiment: Before a test is done, there is an expected result. The test is performed, to show this result. In an experiment, the outcome is open. Very often, tests are performed as part of an experiment.