Cost efficiency comparison of four video-based techniques for assessing upper arm postures

Abstract

Many video-based techniques for assessing postures at work have been developed. Choosing the most appropriate technique should be based on an evaluation of different alternatives in terms of their ability to produce posture information at low input costs, i.e. their cost efficiency. This study compared four video-based techniques for assessing upper arm postures, using cost and error data from an investigation on hairdressers. Labour costs associated with the posture assessments from the video recordings were the dominant factor in the cost efficiency comparison. Thus, a work sampling technique associated with relatively large errors appeared, in general, to be the most cost-efficient because it was labour-saving. Measurement bias and other costs than labour cost for posture assessment influenced the ranking and economic evaluation of techniques, as did the applied measurement strategy, i.e. the numbers of video recordings and repeated assessments of them.

Practitioner Summary: The cost efficiency of four video-based techniques for assessing upper arm postures was compared. Work sampling techniques were in general more cost efficient than continuous observations since theywere labour-saving. Whilst a labour cost dominated the comparison, ‘hidden costs’, bias and measurement strategy also influenced this dominance.

Keywords:

• precision
• bias
• input costs
• measurement strategy
• model specification

Acknowledgments

In writing this article, the authors would gratefully appreciate the contribution of Dr. Apostolos Bantekas, Division of Economics, University of Gävle. The study was supported by grants from the Swedish Council for Working Life and Social Research (FAS DNr.2005-0183 and 2009-1761).