Typing is the process of writing or inputting text by pressing keys on a typewriter, computer keyboard, cell phone, or calculator. It can be distinguished from other means of text input, such as handwriting and speech recognition. Text can be in the form of letters, numbers and other symbols. The world's first typist was Lillian Sholes from Wisconsin, the daughter of Christopher Sholes, who invented the first practical typewriter. According to the study, "The number of fingers does not determine typing speed. People using self-taught typing strategies were found to be as fast as trained typists. Instead of the number of fingers, there are other factors that predict typing speed. Fast typists keep their hands fixed on one position, instead of moving them over the keyboard, and more consistently use the same finger to type a certain letter." To quote doctoral candidate Anna Feit: "We were surprised to observe that people who took a typing course, performed at similar average speed and accuracy, as those that taught typing to themselves and only used 6 fingers on average." Some people combine touch typing and hunt and peck by using a buffering method. In the buffer method, the typist looks at the source copy, mentally stores one or several sentences, then looks at the keyboard and types out the buffer of sentences. Not normally used in day-to-day contact with keyboards, this buffer method is used only when time is of the essence. A late 20th century trend in typing, primarily used with devices with small keyboards (such as PDAs and Smartphones), is thumbing or thumb typing. This can be accomplished using either only one thumb or both the thumbs. Similar to desktop keyboards and input devices, if a user overuses keys which need hard presses and/or have small and unergonomic layouts, it could cause thumb tendonitis or other repetitive strain injury. Words per minute (WPM) is a measure of typing speed, commonly used in recruitment. For the purposes of WPM measurement a word is standardized to five characters or keystrokes. Therefore, "brown" counts as one word, but "mozzarella" counts as two. The benefits of a standardized measurement of input speed are that it enables comparison across language and hardware boundaries. The speed of an Afrikaans-speaking operator in Cape Town can be compared with a French-speaking operator in Paris. In one study of average computer users, the average rate for transcription was 33 words per minute, and 19 words per minute for composition. In the same study, when the group was divided into "fast", "moderate" and "slow" groups, the average speeds were 40 wpm, 35 wpm, and 23 wpm respectively. An average professional typist reaches 50 to 80 wpm, while some positions can require 80 to 95 wpm (usually the minimum required for dispatch positions and other typing jobs), and some advanced typists work at speeds above 120 wpm. Two-finger typists, sometimes also referred to as "hunt and peck" typists, commonly reach sustained speeds of about 37 wpm for memorized text and 27 wpm when copying text, but in bursts may be able to reach speeds of 60 to 70 wpm. From the 1920s through the 1970s, typing speed (along with shorthand speed) was an important secretarial qualification and typing contests were popular and often publicized by typewriter companies as promotional tools. A less common measure of the speed of a typist, CPM is used to identify the number of characters typed per minute. This is a common measurement for typing programs, or typing tutors, as it can give a more accurate measure of a person's typing speed without having to type for a prolonged period of time. The common conversion factor between WPM and CPM is 5. It is also used occasionally for associating the speed of a reader with the amount they have read. CPM has also been applied to 20th century printers, but modern faster printers more commonly use PPM (pages per minute). The fastest typing speed ever, 216 words per minute, was achieved by Stella Pajunas-Garnand from Chicago in 1946 in one minute on an IBM electric using the QWERTY key layout. As of 2005, writer Barbara Blackburn was the fastest English language typist in the world, according to The Guinness Book of World Records. Using the Dvorak keyboard layout, she had maintained 150 wpm for 50 minutes, and 170 wpm for shorter periods, with a peak speed of 212 wpm. Blackburn, who failed her QWERTY typing class in high school, first encountered the Dvorak layout in 1938, quickly learned to achieve very high speeds, and occasionally toured giving speed-typing demonstrations during her secretarial career. She appeared on Late Night with David Letterman on January 24, 1985, but felt that Letterman made a spectacle of her. The recent emergence of several competitive typing websites has allowed several fast typists on computer keyboards to emerge along with new records, though these are unverifiable for the most part. Two of the most notable online records that are considered genuine are 251.21 wpm on an English text on typingzone.com by Brazilian Guilherme Sandrini (equivalent to 301.45 wpm using the traditional definition for words per minute since this site defines a word as six characters rather than five) and 256 wpm (a record caught on video) on TypeRacer by American Sean Wrona, the inaugural Ultimate Typing Championship winner, which was considered the highest ever legitimate score ever set on the site, until Wrona claimed it has been surpassed. Both of these records are essentially sprint speeds on short text selections lasting much less than one minute and were achieved on the QWERTY keyboard.