How DNA helps in solving Forensic crimes.

How DNA helps in solving Forensic crimes.
Forensic science plays a vital role in crime investigation. Police apply this technique in different fields ranging from DNA test to solve crimes. This has further been backed up by the National Research Council (NRC) who has insisted on the need to widen the scope on different fields in forensic science, basing on the fact that DNA is the only method that has shown consistency.
DNA has high affinity to show connection between individual and source of evidence. With the need to improve forensic science NRC filed a report comprising measures which should be applied ,these includes; expanding research on the accuracy, reliability, and validity of forensic methods
and inception of human witness bias. They further advocated elimination of law enforcing agencies control in forensic labs hence solving organization problems.

Over the past decade there have been uncertainty on manifestation of DNA, to solve this dilemma. Smith and Pell (2003) published a satirical systematic review of the effectiveness of parachutes. This case study is directly related to DNA; the same way parachutes has refined the outcome of falling down, DNA has also played a major role in solving of crimes. Some of these major cases solved were deemed to have no solutions as seen in various publications e.g. September 23, 2006, article in the Washington Post (Jackman, 2006) where 40 year case was solved and murder culprit apprehended.
It has been determined that forensic methods are more effective compared to existing investigation methods. This has been attributed by ability of DNA to render a high degree of certainty when relating a sample of DNA with a specific individual. However, there have been unanswered queries concerning DNA application in Crime investigations such as high number of arrest made as compared to traditional methods. There have been also limitation to other investigations with a scenario where latent fingerprint might be used in place of finger print or DNA analysis hence raising issues on utility of DNA. Field experimentation has two scopes (Shadish, Cook, & Campbell, 2001) results obtained from this practices help police inform investigation practices.
DNA is useful in various ways when it comes to solve crimes; various methodology have been used to determine application of forensic technology as applied in police office. These methods include;
The Effect of DNA Testing in Burglary Cases (Roman et al., 2008)
This study was used in five police department in US. National Institute of Justice provided each site with additional resources for conducting DNA analysis on evidence from residential and commercial burglary cases with biological evidence. The outcomes measured in this study included suspect identification, suspect arrest, and referral of the case for prosecution. Its main objective was to determine the effectiveness of DNA in deciphering crimes. This study proved that DNA is more effective as compared to controlled cases which was observed from this districts. Cost factor was also addressed

The Effect of an Expanding DNA Database at Solving Crimes (Dunsmuir et al., 2008
The objective of this study was to determine whether the expansion in the DNA database improved police effectiveness through a times-series analysis of monthly clearance rates, charge rates, and the ratio of charge to clearance rates from 1995 through 2007, inclusively. It involved testing DNA of all inmates and recording the results in existing databases. It was found that increasing use of DNA databases helps the police solve crimes. Though a major concern over time series did emerge.
Quasi-Experimental Assessments of the Effect of DNA on Case Outcomes (Briody, 2004; Schroeder, 2007; Tully, 1998)
This study was aimed at obtaining an existing bias relating to quasi-experimental design that compared criminal justice outcomes in cases with DNA testing relative to cases without DNA testing. This study was done in Australia and presence of DNA evidence affected the acceptance of cases for prosecution. It was found that cases involving sexual offences and homicides were probably to be executed with the presence of DNA evidence. In conclusion, DNA evidence increases the prosecution rate and guilty plea from culprits with cases involving physical assaults.
DNA evidence and testing suggests that these cases were fundamentally different and more difficult to solve.
DNA testing for volume crimes represents an important shift in the way DNA is used in the investigative process. There has been further improvement in DNA testing, DNA databases allows the direct identification of suspects by testing crime scene DNA samples against a database. This has been really helpful when solving crimes. (Briody, 2005; Dunsmuir et al., 2008; Roman et al., 2008)                  

DNA has a major utility in big level of solving crimes in affecting the overall clearance rate, for high volume crimes often committed by repeat offenders. It also helped the police in obtaining new leads.
The use of different forensic methods involve opportunity costs, which can be quite expensive when considering that the choice between options may be the difference between identifying a suspect or not. Understanding the conditions under which a particular investigative approach is more or less likely to lead to success in closing cases is valuable and, as the studies reviewed here illustrate, can be examined through rigorous empirical methods.









References

Briody, M. (2004). The effects of DNA evidence on the criminal justice process. Retrieved from Dissertations and Theses Database. (Australian Digital Theses Program)
Committee on Identifying the Needs of the Forensic Science Community, National Research
Council. (2009). strengthening forensic science in the United States: A path forward (National Academy of Science Report No. 2006-DN-BX-0001). Retrieved from http:// www.ncjrs.gov/pdffiles1/nij/grants/228091.pdf