Ideally, human factors and ergonomics initiatives should be implemented early in the design cycle. This alleviates the potential for costly changes that must be incorporated when discovered later in the design cycle. For example, Hendrick (2003) found that human factors and ergonomics initiatives were 1% of the engineering design budget when implemented early in the design cycle compared to 12% when implemented after the system went online. Moreover, as discussed in the “Why Should Human Factors and Ergonomics Initiatives Should Be Important to Your Organization?” section, early implementation leads to increased cost-effectiveness and a better return on investment (ROI) for the organization.
Although it’s best to implement human factors / ergonomics initiatives early in the design cycle, if unable to do so, it’s still better to implement later than not at all.
References
Hendrick, H.W. (2003). Determining the cost-benefits of ergonomics projects and factors that lead to their success. Applied Ergonomics, 34, 419-427.