Objective: The degree in which practitioners use the observational methods for musculoskeletal disorder risks assessment correctly was evaluated.

Background: Ergonomics assessment is a key issue for the prevention and reduction of work-related musculoskeletal disorders in workplaces. Observational assessment methods appear to be better matched to the needs of practitioners than direct measurement methods, and for this reason, they are the most widely used techniques in real work situations. Despite the simplicity of observational methods, those responsible for assessing risks using these technics should have some experience and know-how in order to be able to use them correctly.

Methods: 442 risk assessments of actual jobs carried out by 290 professionals from 20 countries were analyzed to determine their reliability.

Results: The results show that approximately 30% of the assessments performed by practitioners had errors. In 13% of the assessments the errors were severe and completely invalidated the results of the evaluation.

Conclusion: Despite the simplicity of observational method, approximately one out of three assessments conducted by practitioners in actual work situations does not adequately evaluate the level of potential musculoskeletal disorder risks.

Application: This study reveals a problem that suggests that a greater effort is needed to ensure that practitioners possess better knowledge of the techniques used to assess work-related musculoskeletal disorder risks, and that laws and regulations should be stricter as regards qualifications and skills required by professionals.