stim marker

What Is a Stim Marker?

See: event marker.

Significance in PDD

This concept is part of the theoretical and practical framework supporting psychophysiological detection of deception. Understanding it helps practitioners, researchers, and informed consumers appreciate the scientific foundations of modern polygraph testing and the ongoing refinement of techniques and methods based on empirical research.

Further Reading

For comprehensive information on polygraph science, visit the polygraph glossary, the research database, or the Polygraph Examiner Hub for professional resources.

Professional Context

This concept forms part of the knowledge base expected of qualified forensic psychophysiologists. Training at APA-accredited schools covers the theoretical foundations, practical applications, and research evidence underlying all aspects of polygraph methodology. Ongoing continuing education ensures practitioners stay current with developments in the field.

For information about scheduling a polygraph examination with an APA-professional examiner, visit our online booking page or call to discuss your specific testing needs.

What Is a Stim Marker?

A stim marker (stimulus marker) is an event marker placed on the polygraph chart to indicate the precise moment a question or other stimulus was presented to the examinee. Stim markers are essential for defining the response onset window — the time period after stimulus presentation during which physiological responses are evaluated for scoring.

Function

Without accurate stim markers, the examiner cannot reliably identify which physiological changes are question-related and which are background non-specific responses. In digital instruments, stim markers are time-stamped with millisecond precision and embedded in the chart data file. They are a critical component of the chart marking system.