---
name: expert-deposition
title: Expert Witness Deposition
description: Guides taking or defending U.S. expert witness depositions with Daubert/Frye methodology testing, Rule 26(a)(2) compliance, and Rule 702/703 foundations. Use when building expert deposition outlines, preparing Daubert challenge records, defending expert prep sessions, reviewing expert reports for admissibility, or creating expert testimony lock-in strategies.
author: CaseMark
author_url: https://github.com/CaseMark/skills/tree/main/skills/legal/expert-deposition
license: Apache-2.0
version: 0.1.0
execution_mode: open
jurisdiction: us
practice: litigation
language: en
---

# Expert Witness Deposition

Builds a motion-ready expert deposition record or defense-prep plan targeting Daubert/Frye admissibility. Covers qualification limits, methodology attacks, bias/compensation exposure, and opinion lock-in.

## Prerequisites

1. Venue admissibility standard (Daubert, Frye, or state hybrid) and local expert disclosure rules
2. Rule 26(a)(2) expert report(s) and disclosure materials
3. Expert CV, publications, and prior testimony list
4. Case facts and key documents (reviewed and not reviewed by expert)
5. Alternative theories, critiques, or rebuttal materials

## Quick Start

Begin every expert deposition task with an intake snapshot:

| Field | Detail |
|---|---|
| Jurisdiction | Federal/State, Daubert/Frye, local rules |
| Expert | Name, field, retention side, role |
| Opinions | Enumerated list from report |
| Methodology | Methods, standards, tools, testing |
| Materials | Documents reviewed, gaps, assumed facts |
| Bias | Compensation, retention history, firm ties |

Then choose the appropriate workflow: **Taking** (Deliverable A) or **Defending** (Deliverable B).

## Deliverable A: Taking Expert Deposition

### Outline Structure

```
I.   Qualifications and Boundaries
II.  Engagement, Scope, and Compensation
III. Materials Reviewed and Assumptions
IV.  Methodology and Reliability
V.   Each Opinion (state, basis, certainty)
VI.  Application to Case Facts
VII. Prior Testimony and Publications
VIII.Lock-In and Completeness
```

### Question Bank

| Topic | Objective | Key Lines |
|---|---|---|
| Qualifications | Define limits | "Expertise is X, not Y?" / "How recent is hands-on work?" |
| Engagement/Bias | Expose incentives | "Rate?" / "Percent income from litigation?" / "Prior exclusions?" |
| Materials | Show gaps | "What did you review?" / "Did you see [critical doc]?" / "Independent investigation?" |
| Methodology | Build Daubert record | "Tested? Peer-reviewed? Error rate?" / "Governing standards?" / "Alternatives considered?" |
| Opinions | Lock in | "State opinion precisely." / "Basis and data?" / "Degree of certainty?" |
| Application | Test fit | "Inputs used?" / "If X fact wrong, opinion changes?" |
| Impeachment | Show inconsistency | "In [case/publication] you said ___?" / "What changed?" |

### Lock-In Questions

Always close with:
- "Are those all opinions you intend to offer?"
- "Any opinions not in your report?"
- "Any bases not stated in your report?"

### Daubert/Frye Record Checklist

Flag each ground that applies:

- [ ] Qualifications limited in relevant sub-field
- [ ] Method not testable or not tested
- [ ] No peer review or publication
- [ ] Error rate unknown or unacceptable
- [ ] No governing standards or standards not followed
- [ ] Not generally accepted in the field (Frye)
- [ ] Unreliable application to case facts
- [ ] Insufficient facts/data or unverified assumptions
- [ ] Failure to consider contrary evidence
- [ ] Opinion not helpful to trier of fact (Rule 702)

## Deliverable B: Defending Expert Deposition

### Preparation Sessions

| Session | Goal | Materials |
|---|---|---|
| Report Mastery | Clear explanation of each opinion | Final report, exhibits |
| Methodology Defense | Articulate reliability and fit | Standards, literature, calculations |
| Mock Deposition | Practice hostile questioning | Prior testimony, publications |

### Coaching Points

- Explain, don't advocate
- Stay within expertise boundaries
- Acknowledge limitations without overstating certainty
- Plain language a jury can follow
- Separate counsel-provided facts from independent analysis

### Work Product Boundaries (FRCP 26)

| Protected | Discoverable |
|---|---|
| Draft reports (26(b)(4)(B)) | Facts/data considered |
| Attorney-expert draft opinion communications (26(b)(4)(C)) | Assumptions from counsel |
| Attorney mental impressions | Compensation terms |

### Objection Guide

- "Objection, work product" for draft report inquiries
- "Objection, attorney-client privilege" when applicable
- Preserve objections but allow testimony on facts/data considered

## Pitfalls

- **Wrong standard**: Confirm Daubert vs. Frye vs. hybrid before drafting; methodology attack differs significantly.
- **Opinions beyond report**: Do not allow undisclosed opinions unless strategically beneficial; force explicit lock-in.
- **Evasive coaching**: Credibility depends on clarity and candor; never coach experts to evade.
- **Privilege waiver**: Preserve work-product and privilege objections while allowing proper discovery into facts/data and assumptions.
- **Jurisdictional variance**: Flag local differences in expert disclosure scope and deposition time limits.

## Key Authorities

FRCP 26(a)(2), 26(b)(4) | FRE 702-703 | Daubert v. Merrell Dow | General Electric v. Joiner | Kumho Tire v. Carmichael | Frye v. United States
