Evidence testing follows strict guidelines. This ensures that each test is valid. In order to be valid, a particular test has to be reliable (or reproducible), sensitive, and specific. So, what do these qualifications mean to the forensic scientist? First, the test has to show that results are reproducible or reliable. In other words, the test should produce the same result multiple times for the same samples. If a test shows that a soil sample has a high level of a certain mineral, the test would be reproducible if this result appeared in more than one test. Second, a test must be sensitive in the sense that it identifies the unique characteristics of the sample. For example, a DNA test can identify people based on their unique DNA. Finally, tests are specific if they identify particular substances. A test would be specific if it identified the presence of a particular drug, like cocaine, with no other drugs giving the same result.
The evidence is tested repeatidly to ensure it produces the same results of idenitifcation and comparison. If the same result is produced, it is considered reliable. A test must be sensitive in the sense that it identifies the unique characteristics of the sample. For example, a DNA test can identify people based on their unique DNA. Finally, tests are specific if they identify particular substances. A test would be specific if it identified the presence of a particular drug, like cocaine, with no other drugs giving the same result.
