Scientific Method in Forensic Science

Scientific methods refer to the procedures used by scientists to assemble an accurate interpretation of the world. The application of science in criminal justice systems or criminal or civil law is called forensic science. Forensic science has been used for decades as a vital instrument for establishing innocence or assigning guilt in the criminal justice systems. Deoxyribonucleic acid (DNA) analysis, for instance, gained societal acceptance as early as the 1980s (Shaler, 2011). The novel technological development in forensic science for justice systems has been continuously unfolding, and significant milestones have been achieved since the preliminary phase, where DNA was the only scientific application. The fundamental philosophy behind adopting scientific methods in criminal or civil law is that perceptions and understandings of natural phenomena are subjective to cultural and personal beliefs. Scientific methods help minimize bias or prejudice in the assessor when scrutinizing hypotheses and theories (Redmayne, Roberts, Aitken, & Jackson, 2017). The scientific method involved four critical steps, as discussed below.

Observation and Description of a Phenomenon

            The first step in forensic science is observation and description of a phenomenon (or the group of phenomena) or the problem. The forensic investigator must observe the situation/incidence or the crime scene, defining a question about the scenario. For example, in a crime scene examination involving ballistics, the investigator may observe the impression of a particular bullet in the crime scene. In their legal argument, the defense argues that the defendant could not have possibly shot the victim considering the type of ammunition involved or the point of entry and exit of the bullet on the wound (Shaler, 2011). In such a case, it will be the forensic investigator’s responsibility to provide scientific evidence to dispute the defense argument or claim. The forensic investigation in criminal cases encompasses a broad range of observation, including observing and describing bloodstains and projectile patterns, which are then used to formulate a hypothesis (Redmayne, Roberts, Aitken, & Jackson, 2017).


Formulation of Hypothesis (Or Hypotheses)

A hypothesis is formulated to explain the scenario or phenomenon. The step essentially entails framing of a theory or question to justify the happening. For instance, the crime scene in question may involve the possible use of a particular gun, or the weapon is not yet determined at the investigation point. The question will then be whether or not the bullet was fired from the specific gun in question. The forensic investigation would then be tasked to establish the truth using the scientific method, including conducting firearm examination and analysis of ammunition. The aim here is to determine if the weapon in question was used during the crime’s commission under investigation (Shaler, 2011). The investor will also examine the trajectory paths to establish the direction of the bullet. The hypothesis formulated at this stage is used to quantitatively predict the other phenomenon’s existence or new observation results.

Using Hypothesis Formulated To Predict the Presence of Other Phenomena, Or Outcomes of New Observations

At this stage, a forensic examiner tries to apply the hypothesis already formulated to explain what has been observed. A hypothesis is a testable account of the observed phenomenon or group of phenomena and uses a cause and effect relationship. In this case, the hypothesis is the potential cause (account for observation), and the observation acts as the effect (Shaler, 2011). Much of the work is built on previous research, including conducting a literature review comparing previous and current studies to a similar phenomenon. Science is an evolving discipline where new knowledge and data are discovered and accumulated every day; long-held theories are upheld, challenged, or replaced with more advanced ones (Becker & Dutelle, 2018). As such, an experimental text must be completed by independent experimenters to prove the hypothesis.

Performance of Experimental Tests of Predictions

At this stage, multiple independent experimenters perform controlled experimental tests of the predictions to establish whether the findings support the hypothesis. Forensic examiners contrast an “experimental group” with a “control group.” Repeated experimentation is essential to ensure the outcome is certain, and not just merely coincidental or intended. Controlled experimental tests aim to eliminate prejudice or bias in the results (Redmayne, Roberts, Aitken, & Jackson, 2017). As mentioned earlier, the application of forensics science in the criminal and civil law ensures that justice is served based on the investigation’s accurate and steadfast results (Shaler, 2011). With the improvement in science and advancement in technologies, chances of erroneous prosecution and convictions for the innocent have declined. Forensic experimental tests use any single trace of evidence at the crime scene to predict the hypothesis (Redmayne, Roberts, Aitken, & Jackson, 2017). Culprit is almost certain to be apprehended the minute a strand of a trace of evidence is present in the crime scene.

Forensic science has been applied for decades as a critical instrument for establishing innocence or assigning guilt in the criminal justice system and has proven accurate in establishing the cause of the crime. The accuracy of forensic investigation outcomes is essential for the justice system’s credibility as it reduces bias and prejudice when making judgments and convictions.


Becker, R. F., & Dutelle, A. W. (2018). Criminal investigation. Jones & Bartlett Learning.

Redmayne, M., Roberts, P., Aitken, C., & Jackson, G. (2017). Forensic science evidence in question. Criminal Law.

Shaler, R. C. (2011). Crime scene forensics: A scientific method approach. Taylor & Francis.