From The Ergoweb® Learning Center

Testing Reveals Strengths/Weaknesses of NIOSH Nonpowered Hand Tool Checklist

The validity of a NIOSH nonpowered hand tool checklist was furthered when a significant correlation was found between the checklist scores of 18 tools and a separate evaluation of the same tools for comfort, tool quality, and ability of tool to do the job. However, several checklist questions were answered with opposing responses from raters when evaluating the same tool, suggesting the need for question revision.


The checklist was developed through a literature review and focus group of ergonomists.  The checklist itself is intended to be used by construction workers and is composed of 16 questions: 14 applicable to one-handle tools other than screwdrivers, 14 applicable to screwdrivers, and 13 applicable to two-handle tools.  The questions are weighted, based on degree of ergonomic/safety importance, to produce a score up to 100.  A tool with a score of greater than 90 is considered “good,” 75 to 90 is considered “fair,” and less than 75 is considered “poor”.


Fourteen ergonomists, 40 experienced carpenters and 86 novice carpenters participated in the study that evaluated 18 common used construction tools (i.e., hammers, saws, pliers, utility knives).  First, the subjects evaluated the tools using a five point scale for grip comfort, overall comfort of use, tool quality, and how well the tool would do its intended job.  Participants then used the NIOSH checklist to assess the tools responding with “yes” or “no” answers.


Over 28% of the time, there was significant disagreement within a group (i.e., experienced carpenters) as to individual question response to a given tool.  The authors suggest this was attributed to confusion over checklist wording or differences in assessing the tool relative to the question.  Ergonomists disagreed with the carpenters’ opinion over 10% of the time on individual question response to a given tool which researchers said was likely due to the same reasons.


There was a statistical difference in tool checklist score between ergonomists and carpenters over 36% of the time reflecting significant disagreement in evaluation of 10 of the 18 tools.  However, for 13 of the 18 tools, the maximum difference in checklist scores between groups did not exceed 10 points and the maximum score difference among all tools was 15 points.  With elimination of three checklist questions, this inter-group disagreement became statistically insignificant. 


The authors stated that additional studies are planned to evaluate checklist sensitivity and specificity.



A Dababneh, B Lowe, E Krieg, Y K Kong, and T Waters. “A checklist for the Ergonomic Evaluation of Nonpowered Hand Tools.” Journal of Occupational and Environmental Hygiene 1: D135-D145, 2004.

This article originally appeared in The Ergonomics Report™ on 2005-03-30.