Provided by the American Academy of Forensic Sciences:

• Forensic scientists generally should follow the standards of their respective disciplines.  They should apply with care any assessment methods, technical skill, scientific and other areas of specialized knowledge to legal issues and questions.  They should always strive to do high quality work.
  
  
• Forensic scientists should strive to keep current and maintain competence in their scientific discipline.  Although competence at minimum should be a goal, forensic scientists should strive for excellence.
  
  
• Forensic scientists should demonstrate honesty and should strive for objectivity, by examining scientific questions from all reasonable perspectives and by actively seeking all relevant obtainable data that could distinguish between pla us ible alternative possibilities.
  
  
• Forensic scientists should strive to be free from any conflicts of interest.  They should possess an independence that would protect their objectivity.  Any potential conflicts of interest should be disclosed.  Work on related cases should be avoided or discontinued if objectivity may be compromised.
  
  
• Forensic scientists should undertake cases and give opinions only in their areas of expertise, attained through education, training, and experience.
  
  
• Forensic scientists should attempt to identify, deter, and help eliminate unethical behavior by other forensic scientists through methods such as disc us sion with a colleague, education, and, if unsuccessful, by filing an ethics complaint.
  
  
• It is essential to recognize that honest differences of opinion exist and do not imply unethical behavior by either attorneys seeking out experts with favorable opinions.  Forensic scientists should not be blamed unfairly for unpopular verdicts, hones differences of opinion, or the vagaries of the legal system.
  
  
• Passions against an opposing disagreeing expert, or personal animosity, should not constitute the basis for an ethics complaint.  Ethics complaints m us t be made in good faith.  If based primarily on passion, such ethics complaints themselves are inappropriate.
  
  
• Forensic scientists should present their opinions of fact in concise understandable language, but care m us t be taken since such efforts can result in oversimplification and loss of some precision.  In their efforts to communicate effectively, forensic scientists should strive to be as accurate as possible and avoid distortion.  Every reasonable effort should be made to ensure that others (including attorneys) do not distort the forensic scientist’s opinions.
  
  
• Forensic scientists should strive to instill the highest ethical and scientific standards in their students and colleagues through such means as teaching, supervision, setting a good example, publications, and presentations at meetings.
• Forensic scientists should strive for excellence and the highest degree of integrity.  Forensic opinions should not be based on undisciplined bias, personal advantage, or a desire to please an employer or an attorney.
  
  
• When forensic scientists are asked and appropriately expected to express opinions on a legal issue, they should make every effort to become familiar with the applicable legal criteria in the pertinent jurisdiction.  They should take care to reach only those legal concl us ions that result from proper application of the data to that legal issue.
  
  
• Unlike attorneys, forensic scientists are not adversaries.  They take an oath in court to tell the whole truth. They should make every effort to uphold that oath.
  
  
• When a forensic scientist accepts any privileged information from an attorney, care should be taken to ensure that all such information is kept confidential and does not reach the opposing side.  After accepting such information, forensic scientists should not provide their services to the opposing side unless legally ordered to do so.  Forensic scientists should alert attorneys not to make payment or provide privileged information, if they wish to retain the option to be employed by the opposing side.
  
  

Reference:  Barnett, Peter D.  Ethics in Forensic Science:  Professional Standards for the Practice of Criminalistics, CRC Press, 2001, p143-144