Scantron

Scantron automatically scores tests using a reflective-read technology. After turning on the machine, a teacher submits a test answer key. The Scantron reads the key and compares all other forms submitted against it. If a student answers a question incorrectly, the machine prints the correct answer as well as the student’s total score. The Scantron 888P+ model can grade as many as 40 tests per minute with a 99.9% accuracy rate.

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Reflective-Read Technology

Scantron forms contain an infrared light-reflecting ink. When a form passes under an internal read head, the machine notes where the light has been absorbed by pencil lead.

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Lamps

Six lights scan the form. The first light looks for a black mark on the form’s edge--called the timing track--that indicates answer bubbles follow. The other five lights are aligned with bubble rows A through E.

When a bubble is blank, the light reflects from the form to a phototransistor. When a bubble is marked, the light is not reflected and the machine notes a test answer was selected.

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Source: Scantron

Researched by CHRISTINE FREY/Los Angeles Times