Everybody would undoubtedly have experienced the effects fatigue can have on the performance of one’s body to perform day-to-day functions. Whether’s it’s due to the fact that you’ve been up all night with a sick child or due to a Game of Thrones viewing marathon into the early hours of the morning. Regardless the excuse, the next day you may be feeling particularly flat.

The fact of the matter is that an examiner’s mental state, physiological state, and physical or mental limitations all can affect performance. In some forensic units, examiners can confront large backlogs, held to quotas, or unrealistic turn-around times. In this environment, examiners could become more concerned with case output than the quality of the work. As a result, examiners may hurry through cases, taking shortcuts in the analysis and documentation, and failing to reach an appropriate conclusion.

In 2012, the The Expert Working Group on Human Factors released a report that identified fatigue along with stress, complacency, overconfidence, and task overload as examples of adverse mental states of an examiner. In addition to these mental state changes, physical changes can occur such as eyestrain and back pain from the sheer number of latent print comparisons.

Performance can also suffer due to lack of sleep. In many agencies, an examiner could be called to a crime scene in the middle of the night and then be expected to work a normal latent print caseload the next day without rest. Illness can have detrimental effects, and medications can influence a person’s quality of sleep and daytime alertness.

In a recent article, published in Forensic Science International, a study was done to investigate the impact of fatigue on latent print examinations. The small group of participants ranged in age (26 – 31) and experience (3 – 8 years) were tested both before and after a visual matching task that was designed to induce fatigue. Behavioural accuracy as well as eye gaze were both recorded before and after the test, which allowed the researches to measure and assess the effects of fatigue and allow for a mechanistic explanation of the changes in behavioural performance.

The results from the study showed that examiners tend to alter their looking behaviour or terminate the search process of a latent print when fatigued. They also found that examiners were more likely to make a determination of inconclusive when fatigued in contrast to the pre-exhaust exercise when they were able to make a definitive determination of an identification or exclusion.

The authors noted “that it appeared that fatigue in this context induces participants to give up sooner on a print than is otherwise warranted… examiners might seek out different regions when fatigued, or avoid areas with marginal quality that they might otherwise venture into when less tired.”

The implications from this study just reinforce what latent print examiners have known for some time that, when you’re tired or not feeling the best, you don’t perform the best. Examiners should be aware of these issues mentioned above and know how these issues can affect their performance. So if you’re feeling particularly rubbish on a shift, it may not be good practice to tackle that difficult comparison first thing. With effective use of breaks and time management skills, it would be best to approach the comparison when you’re feeling more alert. So leave that difficult latent comparison for a few hours and come back to it with fresh eyes and greater alertness.

This article is also good for managers to be aware of to properly manage staff welfare and ensure that the working conditions on the office floor are in align with correct furniture ergonomics so as to get the best performance out of their staff.

You can read more about this study by clicking here.