Demystifying Demonstrative Evidence in Family Law: A Legal and Practical Guide

By Christine D. Gille

Family law cases often demand more than just party declarations, spoken testimony or written arguments to fully convey their complexity. Whether the issue is a contentious custody dispute, a domestic violence allegation, or the division of marital property, attorneys are expected to take abstract claims and present them in a way that makes sense to the judge.

Although demonstrative evidence is not expressly mentioned in the California Evidence Code, it has long been recognized in California caselaw as a valuable tool. Demonstrative evidence—such as timelines, spreadsheets, infographics, and calendars—can help attorneys turn complicated information into something understandable and persuasive. At the same time, these types of exhibits must be carefully crafted and presented, as they are subject to strict evidentiary rules and statutes.

This article breaks down the legal framework for demonstrative evidence in California family law as it stands in 2025, explores practical strategies for using such evidence, and highlights the risks attorneys should avoid.

The Legal Framework for Demonstrative Evidence

Understanding and working within the rules of evidence is essential for any family law attorney who wants to use demonstrative evidence effectively. The Evidence Code, strengthened by long-standing case law, provides clear guidance on whether an exhibit will be admitted in court. The process starts with determining relevance to the current case, requires proper authentication, and ultimately depends on weighing the probative value of the evidence against potential risks like prejudice or confusion.

Relevance: The Foundation of Admissibility

Under Evidence Code § 210, evidence is relevant if it has any tendency to make a fact that matters in the case more or less likely to be true. This liberal standard gives family law attorneys some flexibility, but demonstrative evidence must always tie directly to the issues the court is evaluating.

For example:
- A timeline of incidents of domestic violence is directly relevant to custody determinations under amended Family Code § 3044, which creates a rebuttable presumption against awarding custody to a parent who has committed domestic violence.
- A calendar highlighting actual versus claimed parenting time discrepancies is pertinent in disputes over physical custody under Family Code § 3020, which prioritizes the child’s health, safety, and welfare.

Recent Caselaw Developments Responding to Family Code § 3044:
Amendments to Family Code § 3044, effective January 1, 2025, now require judges to make specific findings on the record when deciding whether to apply or overcome the presumption against granting custody to a perpetrator of domestic violence. Judges must address all seven factors listed in subdivision (b) and state their reasoning in writing or verbally on the record (court reporter anyone?). The legislative intent behind this change is to ensure family courts take allegations of domestic violence seriously, facilitate meaningful appellate review, and provide greater transparency in custody decisions, IRMO Willis.^[1]

Demonstrative evidence, such as timelines showing escalating abuse over time or charts summarizing individual domestic violence incidents, especially when admitted, can help the court navigate the precise requirements demanded in both amended § 3044 and caselaw, which state that judicial findings must be based on relevant, admissible evidence submitted by the parties. This also helps in later use of the rulings and in appellate review.^[2]

 Key Case Law on Relevance of Demonstrative Evidence:
The principle of relevance in demonstrative evidence is well shown in caselaw in the case of People v Ham, ^[3] where the court allowed demonstrative materials that helped clarify a witness' testimony. While this case involved criminal law, its reasoning applies in family law settings, especially in disputes where patterns of behavior or inconsistencies in testimony need to be made clear for the court. Ham relied on an earlier California Supreme Court case, People v Kynette,^[4] which held that demonstrative evidence such as the model bomb offered there accurately illustrated an expert's relevant testimony, and found such evidence is admissible when it fairly and accurately depicts such testimony.

Authentication: Showing That Demonstrative Evidence is Reliable

Demonstrative evidence must also be authenticated under Evidence Code §§ 1400-1401. Authentication simply means proving that the exhibit is what the attorney's witness claims it to be. However, without this foundation, even the most visually compelling evidence may be excluded.

For family law attorneys, authentication usually involves tying demonstrative exhibits to admissible documents or testimony. Once the underlying materials are authenticated, the demonstrative evidence that accurately relies on those materials can come in. Examples include:
- Timelines for Custody or Domestic Violence Cases: A timeline summarizing abusive incidents should be corroborated with the underlying police reports, text messages, medical records, or sworn testimony.
- Spreadsheets for Financial Division: A chart summarizing bank balances or property valuations must reference the source documentation, such as account statements or appraisal reports. For accountants' "side-by-sides" to be admissible, they must accurately portray the financial evidence.

Key Case Law:
In People v Goldsmith,^[5] the court emphasized the importance of authentication, ruling that a red-light camera photograph, which could be admitted under California Evidence Code § 250, required foundational evidence to verify its accuracy and reliability. Similarly, Andrews v Barker,^[6] an early chain of evidence case, clarified that demonstrative evidence (of an experiment designed to illustrate a condition in the case) does not need to perfectly replicate reality but must “substantially” represent the events or data it purports to illustrate.

The Balancing Act: Probative Value vs. Prejudice

Even demonstrative evidence that is provably relevant and already authenticated can be excluded under Evidence Code § 352 if its potential for confusing or prejudicing the trier of fact outweighs its usefulness. Judges are especially cautious, even in family law where we have no juries, if evidence seems merely presented to be inflammatory and to bias the court.

Practical Examples:
- A graphically detailed infographic of injuries from domestic violence could risk being deemed overly prejudicial if it evokes an emotional reaction rather than aiding the judge in assessing custody under Family Code § 3044.
- Overloaded charts or timelines with excessive detail could be excluded for being more confusing than clarifying.
 

Key Case Law:
Although there are many cases on whether evidence is more prejudicial than probative, there are few applicable family law cases. In IRMO Smith,^[7] the court’s effort to distinguish between relevant financial evidence and evidence offered by testimony that was too speculative, not credible, and was meant to bias the court against the other party is discussed at length.

In Endicott v. Nissan,^[8] the court accepted as demonstrative evidence, over objection, a crash test that was substantially similar although not identical to the original situation. The test was relevant, probative, not overly complex, and not intended to mislead the trier of fact.

Practical Applications in Family Law

Domestic Violence Patterns Illustrated on Timelines or Spreadsheets

A timeline is a powerful way to demonstrate a series of events, such as instances of domestic violence or patterns of parenting. For example: In a domestic violence case, a timeline summarizing escalating incidents, with dates tied to police reports or hospital records, can give the court a clear picture of abuse under Family Code § 3044.

Timelines help judges make required findings by distilling multiple incidents into a straightforward visual presentation.

A spreadsheet can have the same effect and is often easier for clients to build from their data on hand.

In a legal custody request, a double timeline, contrasting and comparing parties' relative amounts of time spent or steps taken for medical or educational responsibilities can be especially effective.

Calendars for Visitation Discrepancies

Parenting time disputes often involve conflicting claims about who is doing what. A calendar visually comparing the visitation agreed to in a custody agreement versus the visitation that actually occurred can quickly expose a parent’s lack of follow-through. Such tools are particularly relevant under Family Code § 3020, which prioritizes a child’s need for stability and consistency.

Financial Disputes on Spreadsheets

Property division cases involving significant assets or debts benefit from clear, concise financial summaries. For example: A spreadsheet listing marital assets, their appraised values, and the proposed division ensures the court sees exactly what is at stake under Family Code § 2550. Such an exhibit may also facilitate settlement discussions.

High-Conflict Cases Call For Demonstrative Evidence

High-conflict divorce or parentage cases present unique challenges for family law practitioners. These cases often involve elevated levels of hostility, emotional manipulation, and contradictory narratives, making it difficult for judges to discern the truth based solely on declarations or testimony. Whether the conflict centers around custody, property division, or allegations of abuse, demonstrative evidence can serve as a neutralizing force, providing clear, tangible representations of key facts to help the judge focus on the case’s material issues rather than the emotions driving it.

Clarifying Conflicting Narratives

High-conflict cases frequently involve parties presenting starkly opposing versions of events, whether about parenting time, financial misconduct, or domestic violence. Demonstrative evidence can help clarify these disputes, provide a script for impeachment, and create a factual framework for the case. For example:

- Custody Disputes: If one parent claims the other is uninvolved in the child’s life, and should not make legal decisions, a timeline showing attendance at school events, medical appointments, and extracurricular activities can provide a consistent, verifiable record of participation.

- Domestic Violence Allegations: A timeline or spreadsheet supported by police reports, hospital records, and text message exchanges can help the court evaluate patterns of behavior and assess whether the presumption under Family Code § 3044 applies.

Reducing Emotional Manipulation

In high-conflict cases, one or both parties may attempt to manipulate the court by presenting evidence designed to evoke emotional reactions rather than provide clarity. Demonstrative evidence such as charts, timelines, and spreadsheets can counterbalance this by grounding the court in factual evidence rather than dramatic displays.

 Managing Financial Complexity

High-conflict divorces often come with accusations of hidden assets, financial mismanagement, or intentional overspending. Demonstrative evidence can simplify complex financial disputes and ensure the judge has a clear understanding of the monetary issues at stake. For example:

• Spreadsheets for Financial Disputes: A spreadsheet featuring side-by-side comparisons of income, expenses, and assets can help clarify claims of financial misconduct or hidden property.
• Tracing Assets: Diagrams tracking the flow of funds help connect transactions to their sources, ensuring property division under Family Code § 2550 is equitable and transparent.

Demonstrative Evidence and Settlement Negotiations

Demonstrative evidence isn’t just a courtroom tool; it can play a key role in settlement negotiations. In mediation or settlement discussions, visual aids can help clarify complex issues that might otherwise lead to impasse. For example:

- Custody Cases: A shared calendar mapping out potential parenting schedules can help parents conceptualize what a 2/2/5 arrangement might look like, making it easier to reach agreement.

- Property Division: Graphs or tables showing equalized division of community property can clear up misunderstanding about fairness, reducing resentment and encouraging cooperation.

- Support Payments: Side-by-side income summaries can remove ambiguity about each party’s ability to pay spousal or child support.

By using demonstrative evidence in this way, attorneys can streamline trial preparation and increase the chances of resolving disputes outside of court.

Conclusion

Demonstrative evidence can elevate practice in family law by making complicated narratives clear, refuting factually-incorrect allegations, and simplifying huge stacks of documents. By focusing on relevance, authentication, and proportionality, attorneys can better explain their clients’ positions during settlement and ensure their exhibits not only survive objections but resonate with the judge as storytelling devices. Whether summarizing financial data, clarifying custody schedules, or documenting abuse patterns, a well-executed demonstrative exhibit can be the difference between a murky argument and a winning case.

(c) Christine D. Gille (2025) All rights reserved.  Christine D. Gille is a CA Certified Family Law Specialist, litigating and consulting on tough child custody, domestic violence, and complex family law in Los Angeles County. Contact her at Gille | Kaye Law Group, P.C. website: www.gillekaye.com or LinkedIn.