Take our Survey Bookmark and Share
Examining the Evidence

Limiting Bias

Following strict protocols helps ensure that evidence is fully analyzed, and reduces the risk of allowing one’s biases to impact the testing process.

Biases can never be eliminated – they are a fundamental part of a person’s thought process. They can, however, be mitigated and acknowledged during the analysis and presentation of evidence. Labs, officers, and attorneys can take steps to limit the opportunity for biases to influence findings and court room testimony.

Individual Roles in Limiting Bias

There are steps an analyst can take to limit their bias, and these steps should be encouraged by lab management.

Analysts must have a conscious understanding of the types of bias to which they may succumb, so they can use self-reflection to question the reasons behind their actions and conclusions. By feeling part of a large team (e.g., the lab, the state, or the criminal justice system) an analyst may lose sight of his or her role as an independent and objective interpreter of the evidence.

Admitting to mistakes, rather than attempting to cover them up, is one conscious means of avoiding biases (and avoiding wrongful convictions). By directly addressing the importance of remaining objective and independent, labs may be able to reduce the impact of cognitive and motivational biases.

Management’s Role in Limiting Bias

There are practices a lab manager can follow to help limit the extent to which analyst bias influences the interpretation of evidence. For example, detailed case files and lab notes allow outside observers to detect potential biases within a conclusion, to spot circumstances where protocols were violated, and to ensure that evidence has been completely examined before a conclusion was reached.

The use of blind pattern and latent print analysis, and limiting the amount of information that an analyst is given, helps prevent bias at the first stages of investigation. The analyst should be provided nothing more than the evidence to be analyzed.

Lab managers or supervisors may also collect the various conclusions of their analysts, and review them to ensure they are coherent and unbiased.

Analysts should be required to communicate in plain and straightforward ways about evidence wherever possible, and without exaggeration, to limit the admissibility of probabilistic statements of certainty which are not scientifically warranted. They also should be prevented from commenting on aspects of evidence that fall outside of their professional qualifications.