Essay Grading

I was going through a bunch of old magazines and newspapers this week when I came upon an article about some software that was being developed for teachers to use that would grade essays. Over the past weekend I had the opportunity to talk to my aunt who was a teacher and college professor before she retired. She said, “there is nothing better to assess a student's knowledge of a subject, than an essay especially when compared to a true or false or multiple choice exams”.

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