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Forensics: The Real CSI - BBC OU series

Forensics: The Real CSI

“My job is to get to the truth, to speak for those who can't speak for themselves”. 

About the programme

Multiple cameras follow serious crime investigations in real time, revealing the crucial role cutting-edge forensic science now plays in bringing criminals to justice.

To find out more or to watch on iPlayer go to the BBC programme pages.  

A forensic investigator wearing a white gown, hat, and a mask sits at a microscope

Exclusive Interviews

Watch our exclusive interviews with the programmes featured investigators.

Andrew Palmer - Forensic Scientist


Andrew Palmer - Forensic Scientist

What’s it like to be a Forensic Scientist, examining items primarily for the presence of blood and touch DNA?

Tanyah Hall - Forensic Examiner


What does it take to be a Forensic Examiner?

What does it take to be a Forensic Examiner?

Phil Field - Forensic Scientist


Phil Field - Forensic Scientist

What does it take to be a Forensic Scientist, specialising in forensic biology?

Jo Ward - Crime Scene Coordinator


What does it take to be a Crime Scene Coordinator?

What does it take to be a Crime Scene Coordinator?

Lucy Bryan - Forensic Scientist


Lucy Bryan - Forensic Scientist

What does it take to be a Forensic Scientist, specialising in interpreting DNA profiling results?

A model of Albert Einstein

How to think more scientifically

Five ways to develop a more scientific approach to problems.

1. Ask the right question

paper question marks

Photo by Olya Kobruseva from Pexels

The best science doesn’t always start in the lab with an experiment. Finding the right question to ask and formulating it in the most effective way can make all the difference between an experiment that goes well and one that goes badly. A good scientific question can be answered by observation or experiment.  Importantly, the question should not be subjective or based upon personal values or opinions – that is, it should be a question about a matter of fact, not a matter of opinion.

To give a simple example, ‘What is the energy density of Marmite in kCal per 100g?’ is a good scientific question, as it is a matter of fact. In contrast, ‘Is Marmite nicer than peanut butter?’ is not a good scientific question, because taste is a matter of subjective opinion.

Scientific questions are specific and will produce results that are measurable or quantifiable.

2. Make systematic observations

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How often do you really take the time to study something? Looking at what is happening around us or observing how something behaves is a vital step in developing scientific thinking. It converts curiosity to knowledge. Learning to look and to study without drawing conclusions prematurely is an essential step in scientific methodology and thinking. This doesn’t have to be in a laboratory.  You can apply this in your daily life.  

3. Decide on a good research method

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Photo by Michael Burrows from Pexels

It doesn’t matter how much information you collect if it is the wrong information. Planning is the key to successful outcomes. Make sure your method is going to produce results that will answer the question you are interested in. Critically analyse whether the data you plan to collect will effectively enable you to investigate the question of interest. 

This is true beyond practical science – thinking about the aim of an activity before embarking on it enables you to critically assess whether the actions you have planned are going to provide value and progress that aim.  A little bit of time spent planning can save you a lot of time later.

4. Always assess risk

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Risk assessment is a part of scientific thinking and should be dynamic and ongoing throughout an activity. It involves identifying hazards (something that may injure or harm you) and assessing the overall risk for a situation (the likelihood of any individual hazard injuring or harming you). 

A key part of scientific planning is to put control measures in place to reduce and manage the risk from any hazards identified. Risk assessment isn’t a single act of recording these on a form, instead, it is something that is always present in scientific thinking and enables us to both predict potential hazards and actively respond to hazards that may not have been apparent initially.

Remember also that if you are doing research on other people (e.g. in psychology) you also have to consider any risks that you might be exposing them to, and make sure that participating in your research doesn’t cause them harm.

5. Be smart and critical about drawing conclusions

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Photo by ThisIsEngineering from Pexels

Drawing conclusions from data means moving from observation (studying and recording without interpretation) to inference (drawing a conclusion based on reasoned consideration of evidence). It is important to be alert to any biases that may affect the conclusion you are drawing. 

Most importantly, remember that correlation (an association between two variables) does not necessarily equal causation (i.e. that one is responsible for the effect seen in the other). Even when your ‘gut’ tells you that there must be a correlation between two variables and that a linkage is, therefore, real, you need to think about how you could gather further evidence to demonstrate this.

This kind of critical approach is valuable outside of the field of science – next time you watch a news broadcast or read a news story, keep it in mind!

A blue-gloved hand holding a petri dish. Microbes and a pink goo are visible in it.

Can you always believe your eyes? | Minimising bias

As a scientist, you need to be certain you can trust your observations as an unbiased and accurate record of the evidence or results. Is this as simple as it seems though?

A close-up picture of a white fingerprint, possibly covered in dust to capture it

Photo by Immo Wegmann on Unsplash

The application of forensic science depends on a variety of skilled scientists who apply scientific thinking and methodology to a wide range of evidence associated with a crime scene. 

Scientific inquiry relies on being able to ensure that the scientific question being investigated can be answered through observational and experimental approaches, and conclusions drawn need to be based on evidence that is unaffected by personal values, opinions, or expectations.

Although there are sometimes cases of scientific fraud – a serious ethical violation – these are thankfully rare.

How can bias affect a scientific investigation?

When conducting research, scientists try to design our studies to ensure that they give a fair and accurate result. For example, this might involve making sure that materials are handled carefully to avoid contamination, and that measurements are taken and recorded precisely and consistently. Although there are sometimes cases of scientific fraud – a serious ethical violation – these are thankfully rare.

However, scientists are, of course, people and we all have our own biases. Some of these biases can be subtle and could affect the results of our research if we are not careful to control them. There are also other potential sources of error beyond biases, which scientists need to be aware of so that we can control for them. We’ll start with an example of a non-bias potential source of error: the ‘observer effect’.

A man in a white coat and blue gloves uses a microscope to examine evidence.

Photo by Edward Jenner from Pexels under Creative Commons BY-NC-SA 4.0  license

Observer Effect

If you drive a car, you will be familiar with checking tyre pressure. Imagine you are responsible for determining the exact pressure of your tyre as the car stands on the road. Is this possible with the tools you have? You may have answered ‘Yes’ to this, as you have access to an accurate tyre pressure gauge. 

Consider what happens when you take the measurement though – it’s impossible to do this without letting a small amount of air escape, which changes the pressure of the tyre very slightly. This is an example of observer effect: that is when the action of observing (or measuring) something changes the thing being observed.

In forensic investigations, a wide range of evidence is collected from the scene and processed in laboratories. Some samples are direct samples of fluid or fabric which can then be tested themselves. Other evidence can be more indirect. An example of this is fingerprint evidence, which is initially a transfer from an individual’s finger to a surface, and crime scene investigators then take an impression of this for analysis. 

For this kind of evidence, it is vital that investigators are aware of how any processes may affect the samples taken and the protocols and procedures are designed to minimise or remove observer effects. Some forensic processes are ‘destructive’, in that they damage or destroy the trace such that other tests cannot be done later.

...unintentional bias can manifest in the scientist unwittingly undertaking an experiment in a particular way which would influence the result in a particular direction...

Experimenter bias

Whilst observer effects are often easy to identify and control for, it is much harder to eliminate biases. First, a point of terminology: here we are not talking about biases in the sense of opinions or viewpoints (e.g. favouring a particular political party or policy). Rather we are talking about what psychologists call ‘cognitive biases’, and in the specific context of scientific research ‘experimenter bias’. This is the term used to describe occurrences where scientists inadvertently influence an experiment, observation or analysis in such a way as to influence the result of their conclusion (if it was intentional it would be fraud, rather than bias).

This unintentional bias can manifest in the scientist unwittingly undertaking an experiment in a particular way which would influence the result in a particular direction, or only looking at the results of an experiment that confirm what they were originally expecting and ignoring other results which did not confirm their expectations.

It can also lead to an unconscious tendency to preferentially interpret ambiguous evidence as supportive of an outcome they are invested in. This sort of bias is also called confirmation bias because it involves being biased towards interpreting evidence in a way that confirms our expectations. It may surprise you to know that we can all unintentionally fall foul of it, and it is vital that all scientists are aware of the possibility of unintentional experimenter bias in order to avoid it. 

This is important when related to the scientific tests carried out in criminal investigations, where there may be preconceptions of the guilt or innocence of a suspect. 

For this reason, scientists working in these laboratories have stringent procedures and protocols to avoid introducing confirmation bias. This includes only receiving information that is necessary for the processing of samples rather than large amounts of additional information about the case. This minimises expectation effects, in this case referring to the likelihood that the interpretation and perception of the reliability of a result may change as a direct result of the expectations of the scientist interpreting that result.

In simple terms, if a forensic scientist has the expectation that the suspect is guilty and they are presented with ambiguous evidence (e.g. a slightly unclear partial fingerprint or grainy CCTV footage), they might interpret the evidence as suggesting the suspect’s guilt (e.g. focus on similarities in the fingerprint or CCTV image).

In contrast, if they think that the suspect is innocent then they might interpret the same ambiguous evidence as consistent with the suspect’s innocence (e.g. focus on differences in the fingerprint or CCTV image). It is, therefore, necessary for forensic scientists to – as much as is possible – have no expectations about the guilt or innocence of the suspect.

Acknowledging the potential for bias in science isn’t a weakness – it enables us to strengthen protocols and procedures to ensure it doesn’t affect the validity of the final conclusions.

Meet the OU experts

Dr Jim Turner, Senior Lecturer in Forensic Psychology
Dr Jim TurnerSenior Lecturer in Forensic PsychologyVIEW FULL PROFILE
Dr Jim Turner, Senior Lecturer in Forensic Psychology
Dr Jim TurnerSenior Lecturer in Forensic Psychology

Jim was The Open University's academic consultant on Series 1 and 2 of Forensics: The Real CSI.

Jim has been researching and teaching in applied cognitive and forensic psychology since 1997, first at the University of Westminster where he completed his Ph.D. and then, since 2006, at The Open University. Jim’s research focuses on a range of forensic topics, including eyewitness identification, facial compositing, the ‘CSI Effect’, and jury decision-making.

He has worked on a number of OU modules across the psychology curriculum, including producing ‘Living psychology: from the every day to the extraordinary’ (DD210), ‘Forensic psychology: crime, offenders and policing’ (D872) and ‘Investigating forensic psychology’ (DD802).

Dr Claire Kotecki, Lecturer in Biology
Dr Claire KoteckiLecturer in BiologyVIEW FULL PROFILE
Dr Claire Kotecki, Lecturer in Biology
Dr Claire KoteckiLecturer in Biology


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