When it comes to people and work, and how we as HF psychologists approach related problems, workload should always be taken into consideration. So then very often one question that pops up in research is as follows: how can we reduce workload or help people better manage it?
In different fields workload will have slightly different definitions, but in psychology, workload generally refers to the amount of cognitive effort required to complete a task. This also ties in with something known as the Multiple Resource Theory, which was proposed by Christopher Wickens in 1984. This can be measured a few different ways, including interview protocols, but one of the most common methods used by researchers is the NASA TLX.
The NASA TLX is a questionnaire where people rate on a scale of generally 1 to 7 different dimensions of workload. Examples of questions would include "how physically demanding was the task" and "how hard did you work to accomplish your level of performance". You also do "card sorting" or presenting pairs of each of the 7 dimensions and having participants pick which one they think is more important. Here is an example of the form.
So what might a study related to workload look like? This type of research can be done with an impressively wide range of interfaces, everything from video game menus to the dashboards of self-driving cars.
However, for this example, let us use a website.
Say you have a small business and you want to set up a website for orders. You've spent hours on it and it looks beautiful, but now you want to see if it is actually easy for your customers to us. One thing you can do is utilize the NASA-TLX and set a task or two (such as placing a large order for your product) and then have participants fill out the form and complete the card sorting task. Ideally, once you score the responses later, you will have a lower score that indicates the workload associated with the task is low.
Hart, S. G., & Staveland, L. E. (1988). Development of NASA-TLX (Task Load Index): Results of Empirical and Theoretical Research. In P. Hancock & N. Meshtaki (Eds.), Human Mental Load (pp. 239–250). North Holland Press.
Rubio, S., Díaz, E., Martín, J., & Puente, J. m. (2004). Evaluation of subjective mental workload: A comparison of SWAT, NASA-TLX, and workload profile methods. Applied Psychology: An International Review, 53(1), 61–86.
Wickens, C. D. (2008). Multiple Resources and Mental Workload. Human Factors, 50(3), 449–455.