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e-rater® Scoring Engine

Evaluates students’ writing proficiency with automatic scoring and feedback

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About the e-rater Scoring Engine

The e-rater automated scoring engine uses AI technology and Natural Language Processing (NLP) to evaluate the writing proficiency of student essays by providing automatic scoring and feedback. The engine provides descriptive feedback on the writer’s grammar, mechanics, word use and complexity, style, organization and more.


Who uses the e-rater engine and why?

Companies and institutions use this patented technology to power their custom applications.

The e-rater engine is used within the Criterion® Online Writing Evaluation Service. Students use the e-rater engine's feedback to evaluate their essay-writing skills and to identify areas that need improvement. Teachers use the Criterion service to help their students develop their writing skills independently and receive automated, constructive feedback. The e-rater engine is also used in other low-stakes practice tests include TOEFL® Practice Online and GRE® ScoreItNow!™.

In high-stakes settings, the engine is used in conjunction with human ratings for both the Issue and Argument prompts of the GRE test's Analytical Writing section and the TOEFL iBT® test's Independent and Integrated Writing prompts. ETS research has shown that combining automated and human essay scoring demonstrates assessment score reliability and measurement benefits.

For more information about the use of the e-rater engine, read E-rater as a Quality Control on Human Scores (PDF).


How does the e-rater engine grade essays?

The e-rater engine provides a holistic score for an essay that has been entered into the computer electronically. It also provides real-time diagnostic feedback about grammar, usage, mechanics, style and organization, and development. This feedback is based on NLP research specifically tailored to the analysis of student responses and is detailed in ETS's research publications (PDF).


How does the e-rater engine compare to human raters?

The e-rater engine uses NLP to identify features relevant to writing proficiency in training essays and their relationship with human scores. The resulting scoring model, which assigns weights to each observed feature, is stored offline in a database that can then be used to score new essays according to the same formula.

The e-rater engine doesn’t have the ability to read so it can’t evaluate essays the same way that human raters do. However, the features used in e-rater scoring have been developed to be as substantively meaningful as they can be, given the state of the art in NLP. They also have been developed to demonstrate strong reliability — often greater reliability than human raters themselves.

Learn more about how it works.


About Natural Language Processing

The e-rater engine is an artificial intelligence engine that uses Natural Language Processing (NLP), a field of computer science and linguistics that uses computational methods to analyze characteristics of a text. NLP methods support such burgeoning application areas as machine translation, speech recognition and information retrieval.


Ready to begin? Contact us to learn how the e-rater service can enhance your existing program.

Young man with glasses and holding up a pen in a library