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Unfortunately, grading essays is extremely time-consuming, and sometimes grading can be inconsistent. Now there is a computer program that can grade essays as well as humans according to its developer Thomas Landauer. "From sixth graders to first-year medical students, we get consistently good results," says Thomas Landauer, a psychology professor at the University of Colorado who has been working on the program for 10 years.
The program, developed into its present form in 1997, uses "latent semantic analysis," a type of artificial intelligence based on complex mathematical formulas that attempt to mimic the human language function. Developed by Landauer, psychologist Peter Foltz of New Mexico State University and doctoral student Darrell Laham of Colorado, the program can't get bored, rushed, sleepy or forgetful. And this, Landauer says, gives it perfect consistency in grading.
To grade text, operators feed the computer general information about the subject to be tested, which can include from 50,000 to 10 million words entered from course textbooks. The program then assigns a mathematical degree of similarity or distance between individual words used by the textbooks and other words in general use. This allows students to use different words that mean the same thing for example, "physician" and "doctor." The program then evaluates essays against sample tests that have already been graded by human instructors and professors. It then takes the combination of words in the student essay and computes its similarity to the combination of words in the essays to come up with a grade.
The student can expect a grade similar to the one on the sample essay his work most closely matches. To achieve this, the software uses about a gigabyte of computer memory, or ten times that of the average home personal computer. My computer at home has 128 megabytes of R.A.M (random access memory) so my computer would need about eight times more R.A.M to run this program.
The software can also gauge student essays against a single standard essay, or tell students what critical subject matter was missing from their work and where in a textbook they can find it. This computer program not only grades material, it can also help students improve their writing.
When this program was demonstrated at New Mexico State University, it was found that the submitted essays all improved with each revision. All of the students were given
the choice of having their essays graded by a human or the computer, they all chose the computer. Landauer said other possible uses for the program include information retrieval since we can now capture the meaning of text by automatic computer analysis. As of the article in 1997, Excite was already using a proprietary version. Landauer said his team hopes to let individuals, schools and private groups use the new program on a limited basis over the Internet. There is one drawback, though: The system grades knowledge content only, not style or grace. So the student who not only knows his stuff but also writes elegantly will get no extra reward.
Marklein, M. (1998). Essay Grading Software. USA Today