• Validation is based on robust scientific tests which provide practitioners and the wider CJS with confidence and reassurance in the forensic methods, processes and equipment being deployed in laboratories and at scenes.
• Validation is the mechanism in which forensic units ensure methods are fit for the purpose intended and support the production of evidential material for Court that is adequate, relevant, and reliable.

Verification is confirmation through further scientific testing, that a finalised method, process, or equipment, remains fit for the specific purpose intended. In a forensic unit where validation of a finalised method has been undertaken more than once, verification can be conducted with a smaller set of tests to verify that everything still works as it should. Adopting forensic units can undertake verification to demonstrate the process works in their hands as long as the method, process or equipment is deployed in the same way.

• Validation is a continuous iterative process and should be undertaken for all methods a forensic unit intends on using, including those infrequently used.

• The Criminal Justice System benefits from validation as Courts can be reassured that evidence has been produced reliably tested via scientific methods.
• Forensic practitioners benefit as they can deploy these methods knowing they have been robustly tested and signed off by their forensic unit reducing the risk of missing evidence and producing erroneous results.
• Investigators can confidently pursue further lines of enquiries knowing that forensic reports have been produced using validated methods.
• The public can be reassured that forensic evidence is presented to the courts without bias and based on scientific testing.

Validation is an activity that supports confirming that a process has been tested, documented and works for the customer. Processes/tools/methods can be tested by manufacturers but their scope might be wide and not focused on accuracy. Validation focuses on end users and their requirements, providing definitive proof that the process/tool/method works for the customer (for example the investigator) and the output is reliable and accurate when taken to court. 

• Validation should be conducted by trained and competent practitioners in the relevant forensic discipline. Evidence of training and competency should be documented in the appropriate training records.
• Practitioners with different levels of experience should be included in validation; therefore, representative of users of the method.
• Practitioners from the location / base or unit where the method will be used should be included in the exercise.

There are different types of validation, including method validation, instrumental validation and software validation. Each type of validation has its own specific requirements. For forensic units, method validation needs to be conducted in line with the Forensic Science Regulators Code.

• The frequency of validation within forensic science depends on a number of factors, including the type of method or process being validated and the intended use of the results.
• Validation should be conducted for each new method or process, and then reviewed periodically thereafter and consideration given to whether any further validation or re-validation is required. For example: a new DNA analysis method might be validated once before it is put in use. The validation would then be reviewed, and this may identify that the validation could be expanded, or that re-validation is required. Timescales for validation review will depend on the stability of the method.
• In addition to periodic validation review, forensic methods and processes should be validated whenever there are changes to the method or procedure, such as when new equipment is used or when the method is applied to a new evidence type.

A logical sequence of operations, described generically for analysis (e.g. for the identification and/or quantification of drugs or explosives, or the determination of a DNA profile) or for comparison of items to establish their origin or authenticity (e.g. fingerprint/footwear mark/toolmark examination; microscopic identifications).

A series of actions or steps taken in order to achieve a particular end.