When you're hiring an audit and assurance firm, references and case studies aren't just nice-to-haves—they're your primary tool for separating competent practitioners from mediocre ones. A strong track record in your industry and company size is what actually predicts whether an audit will be thorough, compliant, and delivered on time.
Why References Matter in Audit & Assurance
Auditors handle sensitive financial data and regulatory compliance. Unlike hiring a general consultant, you're granting access to your balance sheet, cash flow statements, and internal controls—so you need concrete proof they've done this work before.
References should come from companies comparable to yours in size, complexity, and industry. A firm that's audited three small nonprofits isn't necessarily equipped for a mid-market manufacturing business with international revenue streams. Ask the audit firm to provide at least three references from the past 18 months, preferably from clients in your sector or with similar compliance requirements (SOX, HIPAA, charity commission standards, etc.).
What to Ask References
Don't just call and ask, "Were they good?" Ask specific questions that reveal operational reality:
- Audit timeline: How many months did the audit take? Were there delays? Did fieldwork happen as scheduled?
- Team consistency: Did the same partner and senior manager stay on the engagement, or was there frequent turnover?
- Communication style: How often did the firm communicate findings? Were preliminary results shared before the final report?
- Cost management: Did fees stay within the proposal range, or were there significant overages?
- Remediation support: When findings were identified, did the firm help explain them clearly to the board and management?
- Follow-up: How responsive was the firm to post-audit questions?
These details tell you far more than "they were professional" ever will.
Evaluating Case Studies
Quality case studies should outline a specific problem, the audit approach, and measurable outcomes. Look for:
- Problem definition: What was the audit scope? (e.g., "First-time SOX 404 compliance for a $500M manufacturing company")
- Methodology: What controls were tested? Were control gaps identified and prioritized?
- Outcomes: Did management implement improvements? Did the company achieve compliance? Were any financial restatements avoided?
Vague case studies that say "we improved their financial controls" are marketing fluff. Real case studies mention timelines, specific findings, and what changed as a result.
Red Flags to Watch
A few warning signs suggest the firm may not deliver quality:
- References who can only speak to billing practices, not audit quality
- Case studies over five years old (audit standards change; their methodology may be outdated)
- A firm that can't provide references in your industry or company size
- Promises of "40% faster audits" without explanation of how that's achieved
- Inconsistency between proposal scope and what previous clients experienced
Firm Size and Specialization
A Big Four firm (Deloitte, EY, KPMG, PwC) brings brand recognition and extensive resources; expect fees starting at $75,000+ for mid-market audits, with extended timelines due to methodology complexity. A mid-tier regional firm (Grant Thornton, CliftonLarsonAllen, etc.) often costs $35,000–$60,000 and may be faster for straightforward audits. Niche boutique firms specializing in nonprofits, healthcare, or financial services typically cost $20,000–$45,000 but require stronger references to validate their expertise.
Your choice depends on complexity. A clean, uncomplicated audit at a stable company benefits from a responsive regional firm. A business with acquisitions, complex revenue recognition, or regulatory scrutiny warrants a larger firm's depth.
How to Verify References
Call references directly—not contacts the firm provides via email. Ask if they've worked with the auditor on multiple years or engagements; repeat relationships indicate satisfaction. If possible, ask to speak with both the CFO (who manages day-to-day audit work) and a board member (who cares about independence and quality). These perspectives differ, and both matter.
Getting the Right Comparison
Mercoly helps you compare and evaluate audit and assurance providers side-by-side, making it easier to gather references, review case studies, and match firms to your specific needs in one place.
Frequently Asked Questions
Q: How much weight should I give a firm's size versus their specific experience with my industry? Specific industry experience is typically more valuable than firm size, as long as the firm has capacity and quality credentials. A small firm with 10 audits in your industry often outperforms a large firm seeing your sector for the first time.
Q: What's a realistic timeline to request references and check them before hiring? Allow 2–3 weeks. Get references in week one, conduct calls in week two, and make your decision by week three. Rushed due diligence on auditor selection often costs you later in audit delays or missed findings.
Q: Should I ask a reference about cost, or is that off-limits? It's fair game. Ask what their final invoice was relative to the proposal, whether scope changed, and whether they felt fees reflected the value delivered. Cost predictability matters as much as quality.
Start gathering references today to build confidence in your audit firm selection.