Skip to main content

An official website of the United States government, Department of Justice.

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

About
Contact Us
Subscribe
Topics A-Z

Home
NIJ-Hosted Online Training Courses
Law 101: Legal Guide for the Forensic Expert

Law 101: Legal Guide for the Forensic Expert

Federal Rules of Evidence (FREs)

Archival Notice

This is an archive page that is no longer being updated. It may contain outdated information and links may no longer function as originally intended.

Date Created: August 24, 2023

Side Navigation

Home
Glossary
Resources
Help
Learning Objectives
Terminology
Rules of Evidence and Lay Witnesses
Expert Witnesses
An Expert Witness Overview: How the Process Works
Forensic Expert's Role
Preliminary Report
Formal Discovery
Final Report
Final Trial Preparation
Qualities of an Effective Expert
Direct Examination
Cross-Examination
Ethical Issues
Sources of Scientific Evidence
Employer Diversity
Testing or Evaluating Evidence and Writing Reports
Maintaining a Chain of Custody
A Chain of Custody: The Typical Checklist
Discovery of Information
Maintaining Laboratory Information
Documenting Findings
Sample Interrogatories and Criminal Discovery Requests to Produce Expert Testimony
Reviewing Other Analysts' Work
Report Writing and Supporting Documentation
Using Plain Language in Reports
Removing Documents From the Case File
Understanding How Laws Differ Among Jurisdictions
The Preliminary Report
Limitations of the Preliminary Report
Consulting Accredited Standards for Case File Requirements
Surveying the Professional Literature
Following Lab Policies for Report Writing
Including All Conclusions
Completing the Report Review (QA/QC)
Amending Reports
The Final Report
Submitting the Report to the Proffering Attorney
Retaining Samples for Future Testing
Destructive Testing
Knowing Relevant Lab Policies for Evidence Disposition
Report Writing for the New Rules
Importance of Case Preparation
Introduction: Communicating With Attorneys
Problem Areas When Communicating With Attorneys
Techniques to Improve Communication
Philosophical Differences
Engaging the Expert
Expert's Background and Qualifications
Initial Contact
Specific Responsibilities
Dates and Deadlines
Engagement Letter or Directive
Compensation
Importance of Ethical Considerations
Preparation: Qualities of an Effective Expert
Thorough Investigation
Ability to Teach
Competence
Believability
Ability to Persuade
Enthusiasm
Keeping Current and Competent
Professional Societies and Associations
Continuing Education
Journals and Publications
Research, Teaching and Writing
Maintaining an Active Practice in the Field
Curriculum Vitae
Getting Started: The Action Plan
Benefits of Pretrial Preparatory Meeting
Multidisciplinary Cases and Multiple Experts
The Scientific Method
Facts of the Case
Objectivity vs. Advocacy
Facts That Have No Impact on Results
Visual and Demonstrative Aids
Eleven Steps Toward Admissibility
Theory of the Case
Developing Possible Hypotheses
Formulating a Working Hypothesis
Background on the Discipline
Pitfalls of Selective Fact Gathering
Causes of Selective Fact Gathering
Avoiding Pitfalls of Selective Fact Gathering
Challenges Within the Discipline
Opinions and Conclusions
Rules for Experts
Rules for Experts (FREs): 701-706
Shifts in Admissibility Standards
Subpoenas vs. Promises to Appear
Legal Requirements for Subpoenas
Failure to Honor a Subpoena
Failure to Appear
Subpoena duces tecum
Scheduling Matters
Permission to Speak With Attorneys
Speaking with Opposing Counsel
Contacting Opposing Parties
Affidavits
Legal Requirements of an Affidavit
Administering an Oath
Using Affidavits in Place of Testimony
Rules for Arrest Warrants and Affidavits
Grand Juries
Probable Cause Hearings
Being a Court-Appointed Expert
Court-Appointed Experts and Witnesses
Reasons to Appoint an Expert Witness
Testimony by Court Experts About Other Experts' Testing
Federal Rules of Evidence Regarding Expert Witnesses
Cross-Examining Court-Appointed Witnesses
Court-Appointed Non-Expert Witnesses
The Special Master
Discovery
Definition and Purpose of Discovery
Effects of Discovery on Experts
Role of Experts in the Discovery Process
Specific Tasks for the Expert
Role of Expert in Compiling Information
Rules of Discovery for Experts
Criminal Rules vs. Civil Rules of Discovery
Rule 15
Procedures Which Govern Civil Discovery
Rules That Apply to Experts
Discoverable Information
Electronic Media and Discovery
Early Attorney Consultation
Importance of Maintaining Current and Complete Documents
Generating Additional Discovery Requests
Discovery: Role of Consulting Experts vs. Testifying Experts
Confidentiality and Privilege Between Expert and Attorney
Basic Rules
Privilege and the Expert
Retaining Confidentiality
Federal Rules of Civil Procedure, Rule 26(b)(4) & Experts
Limited Privileges
Ethical Conduct and Discovery
Discovery Ethics
Meticulous Preparation of All Materials Subject to Discovery at Deposition or Trial
Orders for Production
Deposition
Review of Discovery Items Before Deposition and Trial
Conclusion
General Testifying Tips
Testimony of Subpoenaed Witness
Handling Schedule Conflicts
Overview of Expert Testimony Preparation
Review of Legal Instructions for Testimony
Structure and Organization of Expert Testimony
Personal Appearance and Demeanor for Testimony
General Observations and Objectivity of the Expert Witness
Expert's Answers to Questions
Expert Must Stay Within the Confines of Expertise
Fundamental Guidelines for Deposition and Trial Testimony
Tips for the Expert Witness in Direct and Cross-Examination
Important Points to Remember
Some Key Observations
Nine Traits of an Effective Expert
Additional Rules for Excellence
Additional Tips for the Novice or Experienced Expert
Value of Expert Witness Post-Testimony Self-Evaluation
Establishment of an Expert Witness "Bill of Rights"
Understanding the Expert's Rights As a Witness
Assertion of the Expert's Rights as a Witness
Observations
Avoidance of Ethical Violations
Examples of Abuses by Experts
Response to Claims of "Junk Science"
Countering Claims of "Junk Science"
Depositions
Definition of a Deposition
Purpose of a Deposition
Authorization of Depositions
Notification of an Expert Before a Deposition
Procedure for Conducting a Deposition
Uses of Depositions
Defendants' Access to Postconviction DNA Testing
States' Postconviction Statutes
Preparation for Deposition
Documents and Materials the Expert Should Review Before Deposition
More Specific Preparation for Deposition
Checklist: Things to Do Before and During the Deposition
Advanced Preparation for Deposition
Prior Writings and Testimony Contrary to the Case's Position
Organizing Prior Writings and Testimony
Maintaining Credibility
Exercising Caution About Opinions, Omissions and Responses at Deposition
Answering Questions Effectively in Deposition
Techniques for Effective Testimony in Deposition
Inside Information About Attorneys for Expert Deponents
Value of the Expert Attending an Opposing Expert's Deposition
Pretrial
Pretrial Summary
Pretrial Conference
Discovery Production
Admissibility
Pretrial Motions
Disclosure Hearing
Motion to Suppress
Additional Evidence Testing
Chain of Custody
Retesting by the Offering Party
Independent Testing
Replicate Testing
Additional Testing by the Opposing Party
Retesting by the Offering Party
Independent Testing
Replicate Testing
Additional Testing by the Opposing Party
Retesting by the Offering Party
Independent Testing
Replicate Testing
Additional Testing by the Opposing Party
Retesting by the Offering Party
Independent Testing
Replicate Testing
Additional Testing by the Opposing Party
Retesting by the Offering Party
Independent Testing
Replicate Testing
Additional Testing by the Opposing Party
Retesting by the Offering Party
Independent Testing
Replicate Testing
Additional Testing by the Opposing Party
Retesting by the Offering Party
Independent Testing
Replicate Testing
Pretrial Rules of Evidence
Relevance
The Frye "General Acceptance" Standard
Daubert and Kumho Decisions
General Admissibility Factors
Testing Methodology
Qualifications of the Expert
Testing Methodology of the Relevant Discipline
Peer Review
Error Rates of Techniques and Laboratory Testing
General Acceptance
State Standards for Admissibility
Final Trial Preparation
Final Status Conference
Proceeding to Trial Without a Final Status Conference
Other Sources of Help
Final Trial Preparation Checklists
Trial Preparation Without Assistance From Counsel
Useful Steps for Self-Preparation
Trial
Definition of a Trial
Types of Evidence
Relevancy of Evidence
Requirements for Evidence Admissibility
Experts Can Give Their Opinion
Some Admissibility Determinations
Pretrial Motions
Motions in Limine & Forensics
Sequestration
Use of an Expert Witness at Trial
Qualifying the Expert
A Typical Balance Struck by FRE
Criminal Defendant Can Be Confronted by Accusers
A Typical Balance Struck by FRE
Criminal Defendant Can Be Confronted by Accusers
The Structure of Direct Examination
Consequences of Not Dealing With Weaknesses
Exhibits and Visual Aids
Referring to Notes or the Report
The Expert's Role
Effective Expert Testimony
Five Main Parts of Direct Testimony
Seven Fundamentals for the Effective Expert
Important Traits That Enhance Expert Witness Credibility
Teaching Skills and Direct Examination
Important Points to Remember for Direct Examination
Key Advice Learned by Experience
A Typical Balance Struck by FRE
Criminal Defendant Can Be Confronted by Accusers
The Structure of Direct Examination
Consequences of Not Dealing With Weaknesses
Exhibits and Visual Aids
Referring to Notes or the Report
The Expert's Role
Effective Expert Testimony
Five Main Parts of Direct Testimony
Seven Fundamentals for the Effective Expert
Important Traits That Enhance Expert Witness Credibility
Teaching Skills and Direct Examination
Important Points to Remember for Direct Examination
Key Advice Learned by Experience
More Observations for the Effective Expert Witness
Tone of Voice
Enhancing Direct Examination
A Typical Balance Struck by FRE
Criminal Defendant Can Be Confronted by Accusers
The Structure of Direct Examination
Consequences of Not Dealing With Weaknesses
Exhibits and Visual Aids
Referring to Notes or the Report
The Expert's Role
Effective Expert Testimony
Five Main Parts of Direct Testimony
Resources
Seven Fundamentals for the Effective Expert
Important Traits That Enhance Expert Witness Credibility
Teaching Skills and Direct Examination
Important Points to Remember for Direct Examination
Key Advice Learned by Experience
More Observations for the Effective Expert Witness
Tone of Voice
Enhancing Direct Examination
Qualities of Effective Direct Examination
Tips for Trial Testimony
Becoming a Better Witness
Simplifying the Complex During Direct Examination
The Attorney's Role
Visual Aids
Cross-Examination
Effective Tips for Cross-Examination
Impeachment in Context of Forensics
Seven Key Traits for Successful Cross-Examination
Preparation for Cross-Examination
Addressing Claims of "Junk Science"
Further Preparation Points for Cross-Examination
Use of Hypothetical Questions
Important Points to Remember During Cross-Examination
More Ways to Reduce Vulnerability on Cross-Examination
Examiner Techniques on Cross-Examination
Body Language
Additional Examiner Techniques
The Attorney's Role
Topic 10: The Fact Finder (Jury)
Jury Instructions
Post-Conviction
Motion for a New Trial
Evidence Retesting
Special Circumstances (Death Penalty)
Post-Testimony Self-Evaluation
Ethics for Experts
Ethical Issues
Ethical Problems
Primary Ethical Issues
Ethical Violations
Methods of Challenging Forensic Fraud and Unethical Behavior
Inadequate Preparation and Ethical Violations
Improving Expert and Counsel Relationships
A Typical Code of Conduct
Expert Malpractice
Expert Malpractice Cause of Action
Serious Deficiencies in U.S. Forensic Science
Appendix
Course Map
Sample Interrogatories and Request for Production to Expert Witnesses
A Proposed Code of Conduct, American Academy of Forensic Sciences, Jurisprudence Section, Code of Professionalism
Sample Engagement Letter From Retaining Attorney
Sample Engagement Letter From Expert Witness
Federal Rules of Evidence (FREs)
Sample Interrogatories and Request for Production to Expert Witnesses
Evaluation and Use of Visual Aids
Items Required For Testimony
Questions That Experts Should Be Prepared to Answer
Positive Qualities for Effective Testimony
More Testimony Suggestions
Testimony Tips From Trial Judges
Importance of Demonstrating Lack of Bias
The Fact Finder (Jury)
Post-Trial, Pre-Sentencing
Ethics Codes and the Expert's Ethical Obligations
Forensic Professional Codes of Ethics
Deposing An Adverse Witness
Key Issues in Reference to Hearsay
Hearsay Exceptions
Federal Rules of Evidence Regarding Hearsay
Forensic Professional Codes of Ethics and Conduct

Top

National Institute of Justice

About NIJ

About NIJ
How NIJ Is Organized
NIJ Director
Research Disclaimer

Funding & Awards

Funding & Awards Home
Awards Listing
Current Funding
Guidance for Applicants and Awardees

Resources

Events
Podcasts
Publications
Topics
Multimedia
Reuse Policy

Contacts

Contact NIJ
Staff Directory
Submit a FOIA Request
File a Civil Rights Complaint

Facebook X YouTube

810 7th St. NW, Washington, D.C. 20531

Secondary Footer link menu

Accessibility
Plain Language
Privacy Policy
Legal Policies and Disclaimer
No FEAR Act
Freedom of Information Act
USA.gov
Justice.gov