Clear, data-driven analysis and expert testimony in matters involving paid search, SEO, social media, analytics, attribution, and digital advertising.
Expert Reports · Rebuttal Reports · Depositions · Trial Testimony · Consulting
View Expert Services Discuss a CaseDigital marketing encompasses the online platforms, tools, and strategies that businesses use to promote products, services, and brands through electronic channels. It includes paid search advertising (PPC), search engine optimization (SEO), social media marketing, display and programmatic advertising, email marketing, content marketing, affiliate programs, and the analytics and attribution systems that measure their performance.
When disputes arise involving digital marketing, the technical complexity of these channels often requires an expert witness who can analyze the evidence, explain what happened, and present findings in a format that attorneys, judges, and juries can evaluate. That is what Bill Hartzer provides.
Detailed expert reports analyzing digital marketing evidence, including rebuttal reports responding to opposing expert opinions. Deposition and trial testimony that translates technical marketing concepts into clear, accessible language.
Learn more →Independent review of paid search campaigns, SEO programs, social media strategies, display advertising, and email marketing to determine whether industry standards were met and whether performance claims are supported by data.
Learn more →Validation of analytics implementations, conversion tracking accuracy, attribution models, and ROI calculations. Analysis of whether reported marketing results are reliable and whether damages calculations are methodologically sound.
Learn more →Investigation of click fraud, invalid traffic, ad misplacement, deceptive advertising practices, and violations of platform policies or regulatory requirements in digital advertising.
Learn more →Digital marketing disputes arise in a variety of legal contexts. The following are among the most common case types where Bill Hartzer provides expert analysis and testimony.
Analysis of digital advertising campaigns, landing pages, and promotional content to determine whether marketing representations were deceptive or misleading.
Breach of contract, negligence, and performance disputes involving SEO agencies, PPC management firms, and marketing consultants.
Investigation and quantification of fraudulent clicks, bot traffic, and invalid impressions in paid advertising campaigns across search, display, and social platforms.
Evaluation of marketing attribution models, conversion tracking accuracy, and analytics data reliability in cases involving performance-based compensation or damages calculations.
Analysis of trademark use in paid search ads, display campaigns, social media promotions, and affiliate programs, including keyword bidding on competitor trademarks.
Assessment of how negative content, reviews, or search results affect a business's digital marketing performance, online visibility, and customer acquisition.
Reconstruction of organic and paid traffic performance to quantify lost visitors, leads, and revenue resulting from the actions or negligence of another party.
Analysis of product listing optimization, marketplace advertising spend, and promotional strategies on platforms such as Amazon, Shopify, and similar e-commerce channels.
Bill Hartzer's expert opinions are built on transparency and replication. Every analysis follows a structured methodology that opposing counsel and the court can examine, test, and challenge.
The process begins with a thorough review of the available evidence, including campaign data, analytics reports, platform exports, contracts, and communications. The analysis identifies what actions were taken, what results occurred, and whether a causal connection exists between the two. Findings are presented in plain language, with supporting data and documentation that allows independent verification.
This evidence-based approach ensures that expert opinions are grounded in data rather than speculation, and that conclusions can withstand scrutiny under cross-examination and applicable evidentiary standards including Daubert.
Bill Hartzer has worked in digital marketing since the late 1990s, with deep experience across search engine optimization, paid search advertising, social media, analytics, and attribution. He is the founder of Hartzer Consulting and has served as an expert witness in legal matters involving digital marketing disputes, providing independent analysis and testimony for both plaintiffs and defendants.
His hands-on experience managing real campaigns across multiple channels ensures that his expert opinions reflect current industry practices and platform behavior, not just textbook theory.
Read Full BioBill Hartzer has direct, hands-on experience with the major platforms and tools that form the foundation of modern digital marketing. His expert witness work regularly involves analysis of data from the following.
Google Ads, Microsoft Advertising (Bing Ads), Google Search Console, Google Analytics (UA and GA4), and third-party SEO and rank-tracking tools.
Meta Ads (Facebook and Instagram), LinkedIn Advertising, YouTube Ads, programmatic display platforms (DSPs), and social media management tools.
Google Analytics 4, Adobe Analytics, call-tracking systems, CRM platforms, marketing automation tools, and multi-touch attribution solutions.
Digital marketing expert witness engagements typically follow a structured process designed to ensure thoroughness, independence, and compliance with litigation requirements.
A brief case summary allows Bill to assess the digital marketing issues involved and confirm that no conflicts exist.
Together with counsel, the scope of the engagement is defined: expert report, rebuttal, deposition, trial testimony, or consulting.
Relevant data, documents, and platform records are reviewed and analyzed using the methodology described above.
A detailed expert report is drafted, presenting findings, methodology, data sources, and conclusions in a defensible format.
Bill is available for deposition and trial testimony, explaining technical digital marketing concepts in clear, accessible language.
Contact Bill Hartzer to discuss how digital marketing expert analysis can support your case.
Contact Bill Hartzer