Inter-observer reliability of forceful exertion analysis based on video-recordings

Area of Science:

• Occupational Health
• Ergonomics
• Industrial Hygiene

Background:

• Accurate measurement of forceful exertions in job tasks is crucial for assessing occupational risks.
• Previous studies have highlighted variability in observational methods for quantifying physical demands.

Purpose of the Study:

• To evaluate the inter-observer reliability of job-level forceful exertion analyses.
• To assess the temporal agreement of detailed time study results for exertion parameters.
• To determine the reliability of different components of forceful exertion measurement.

Main Methods:

• Three observers analyzed 12 different jobs using detailed time study methods.
• Collected data included continuous duration, frequency, and percentage of time for specific forceful exertions (lifting, pushing/pulling, gripping).
• Statistical analyses included intraclass correlation coefficients and variance components for reliability, and temporal agreement analyses for time data.

Main Results:

• Good inter-observer reliability was found for most job-level exposure parameters (duration, frequency, % time).
• Reliability was fair to moderate for the estimated level of forceful exertions.
• Between-observer variability was less than between-exertion variability, indicating the method's ability to detect job differences.
• Achieving majority consensus among three observers increased agreement to 97%.

Conclusions:

• Job-level exposure measurement of forceful exertions using detailed time studies demonstrates generally good inter-observer reliability.
• Observer ability in estimating the *level* of forceful exertion can be a limitation.
• Findings provide guidance for improving agreement in studies requiring synchronized measurements.