Executive Due Diligence: What the Current Framework Cannot Measure

Don L. Gaconnet, CSE III LifePillar Institute for Structural Identity Sciences · Lake Geneva, Wisconsin

Every pillar of due diligence uses an independent instrument. Financial diligence has the audit. Legal diligence has the compliance review. Operational diligence has the systems assessment. Technology diligence has the infrastructure evaluation. ESG diligence has the risk framework. Each pillar relies on an instrument that measures something the deal team cannot see by looking at the numbers — and each produces a finding that goes in the file.

Except the person the capital depends on.

The person — the CEO, the founder, the key executive carrying the deal thesis on their back — gets an interview. A behavioral assessment. A personality profile. A four-hour psychological evaluation that one of the industry's own firms has described as producing "very little data of predictive value." The person who determines whether the investment returns its capital is the only element of the deal evaluated without an independent instrument.

This is the gap. It is measurable. It is costly. And it is the reason 65% of private equity firms replace the CEO during the hold period while 83% report that the replacement extended the timeline and reduced returns.

The Due Diligence Framework Is Missing a Line Item

The modern private equity due diligence framework has expanded significantly over the past decade. What was once a three-pillar structure — financial, legal, operational — now routinely includes five to nine workstreams. Technology diligence was added when digital infrastructure became a value driver. ESG diligence was added when governance risk became a liability. Commercial diligence was added when market positioning became a deal-level question. Each addition followed the same pattern: someone recognized that a material risk existed outside the existing framework, an independent measurement methodology was developed to assess it, and the new pillar became standard practice.

The human capital workstream exists. It appears on every due diligence checklist published by every advisory firm in the market. But its contents reveal the gap. The human capital workstream evaluates leadership quality through behavioral interviews, personality assessments, reference checks, 360-degree feedback, and structured self-report. Every methodology in the workstream depends on one of two data sources: what the executive says about themselves, or what others observe about the executive's behavior.

Neither data source reaches the structural condition that determines whether the executive can carry what the deal thesis requires.

This is not an incremental limitation. It is a category-level absence. Every other pillar of due diligence uses an instrument that measures something the subject cannot control, conceal, or perform past. Financial diligence reads the books — the CEO cannot narrate the books into compliance. Legal diligence reads the contracts — the general counsel cannot interview the contracts into enforceability. The leadership assessment reads the executive's behavioral presentation, and the executive under maximum professional load is performing at maximum capacity to present well. The assessment reads the performance. The performance is what the assessment was designed to bypass.

The due diligence checklist is missing a line item: independent, instrument-based measurement of the structural capacity of the person the capital depends on. Not what the executive says they can do. Not what the executive's references observed them doing. What the executive's system can actually sustain — measured independently, without self-report, through an instrument the executive cannot manage.

Why Leadership Assessment Keeps Failing in Private Equity

The data on CEO turnover in private equity has reached a density that makes the pattern undeniable. In 2025, CEO departures hit a record 234 globally — up 16% from the prior year and 21% above the eight-year average. CEO tenure dropped to 7.1 years. The S&P 500 is on track for a 13% succession rate, up from 10% the year before. Q1 2026 saw 77 new CEO appointments across the S&P 500, FTSE 100, and DAX 40 — the highest first quarter in at least eight years.

The critical finding is not the volume. It is where the turnover is occurring. CEO successions at S&P 500 firms in the top three performance quartiles jumped from 7% in 2024 to 12% in 2025. Boards are replacing CEOs who are performing well. Performance is no longer the question. The question has shifted: Can the CEO carry what the next phase requires?

That question cannot be answered by behavioral assessment. Behavioral assessment reads what the executive is producing — the output, the presentation, the observable competencies, the leadership behaviors visible to evaluators. When the executive is performing well, behavioral assessment confirms the performance. The methodology is structurally incapable of detecting the gap between current output and sustainable capacity. The assessment reads the surface because the surface is what behavioral methodology was designed to read.

The market's own practitioners have begun to say this out loud. "Most leadership assessments done during M&A due diligence are theatre," wrote Anirvan Sen, an M&A advisor, in April 2026. "Deals do not fail because the model was wrong. They fail because the people charged with delivering the model could not or would not do so." AlixPartners, after conducting eleven annual surveys documenting the same CEO turnover pattern, concluded: "Too many private equity firms are still reacting to leadership crises instead of preventing or anticipating them." Heidrick & Struggles, in their 2026 "Route to the Top" report, found that more than a third of U.S. companies still do not have a CEO with the capabilities needed for near-term success — and this after those companies used the assessment methodologies the market currently offers.

The assessment is not failing because the assessors are incompetent. The assessment is failing because the methodology reads the wrong layer. Leadership due diligence, as currently practiced, evaluates the executive's behavioral presentation — what the executive does, says, and shows. Behavioral interviews read conscious self-report. Personality profiles read trait patterns. Reference checks read observer impressions. Each of these reads the executive's output — what the executive does, what the executive presents, what others see. None of them reads the executive's structural condition — the actual load the system is carrying, the gap between what the role demands and what the system can sustain, the trajectory of that gap over time.

Published research confirms the structural limitation. A JAMA Network Open meta-analysis across 57 studies and 26 countries found that the concordance between structured clinical interviews — the gold standard of assessment methodology — is functionally unreliable. When two independent assessors use the same structured interview on the same subject, they reach the same conclusion only marginally better than chance for many diagnostic categories. If the gold standard methodology produces unreliable agreement between trained assessors, the less structured interviews used in executive assessment carry the same limitation at lower rigor. The methodology's ceiling is well-documented. It has not been addressed because the methodology is the market standard, and the market has not had an alternative.

The Difference Between Reading Performance and Measuring Capacity

The distinction is structural, not semantic. Performance is what the executive produces. Capacity is what the executive's system can sustain. Under normal conditions, performance and capacity are coupled — the executive performs because the executive has capacity, and the performance reflects the capacity. Under load — the kind of load a PE-backed CEO carries during a platform build, a carve-out integration, a compressed hold period with record entry multiples and a deal thesis that demands transformation — performance and capacity decouple.

The executive under load performs at maximum output precisely because the load demands it. The behavioral presentation remains strong or even intensifies. The leadership behaviors the assessment measures — decisiveness, communication, strategic thinking, stakeholder management — continue to present at high levels. The executive is performing. What the assessment cannot detect is the cost of the performance. The gap between what the executive is producing and what the executive's system can sustain is not visible in the behavioral output. It is not accessible through self-report — the executive under maximum load cannot accurately assess their own structural state, not because of dishonesty, but because the load itself degrades the self-assessment function. Published research on self-report reliability under structural load documents this finding: the conditions that make accurate self-assessment most critical are the conditions that make self-assessment least reliable.

This is the IS/DOES distinction. Every assessment methodology in the current market reads what the executive DOES — the behavioral output, the observable performance, the self-reported experience. None reads what the executive IS — the actual structural state of the system carrying the load. The behavioral presentation is real. It is genuinely produced, genuinely observable, genuinely scorable. It does not carry the information that determines whether the executive will sustain through year two of the hold period, or whether the performance is consuming capacity faster than the role allows it to regenerate.

The distinction matters because capital decisions are made on it. When a PE firm evaluates whether the current CEO can carry the next phase, or whether an external hire can execute the deal thesis, the assessment produces a finding based on the executive's behavioral presentation. If the presentation is strong, the finding is favorable. If the executive is performing at maximum output while the structural gap is widening, the finding is favorable until the gap reaches the threshold — which, in the data, spikes at year two.

What Cognitive Due Diligence Measures — and What It Replaces

Cognitive due diligence is the independent, instrument-based measurement of the structural capacity of the person the capital depends on. It does not replace financial diligence, legal diligence, or operational diligence. It does not replace the behavioral assessment. It measures what the behavioral assessment cannot reach — the executive's actual structural condition, measured through an independent instrument that does not depend on self-report, behavioral observation, or interviewer interpretation.

The term is precise. "Cognitive" refers to the structural system being measured — not cognition in the colloquial sense of thinking, but the full architecture of the executive's processing capacity, load configuration, and sustainable output. "Due diligence" places the measurement where it belongs — in the deal file, alongside the financial audit, the legal review, the operational assessment. This is not coaching. It is not therapy. It is not executive development. It is an engineering measurement that produces a finding, and the finding goes in the file.

Cognitive due diligence sits in the framework as the fifth pillar — or the sixth, seventh, eighth, or ninth, depending on how the firm structures its workstreams. The specific position matters less than the structural characteristic: it is independent (conducted by a practitioner with no search firm affiliation, no placement conflict, no advisory relationship with the executive), it is instrument-based (the measurement does not depend on the executive's self-report or the assessor's subjective interpretation), and it produces a finding that meets the standard the deal file requires — specific, defensible, documented, and reproducible.

The credential behind the measurement is engineering, not clinical. Cognitive Systems Engineering (CSE III) is the professional classification. The practitioner background is 27 years of field service engineering across military, government, and Fortune 500 populations — measuring how human systems operate under load, not through interviews, but through instrumented assessment of the system's actual structural state. The published research supporting the methodology is archived on SSRN and OSF, independently verifiable, and grounded in empirical findings with documented convergence across multiple independent data sources.

The Year-Two Problem and the Cost of Late Detection

AlixPartners has now conducted eleven annual surveys documenting the same pattern: 65% of private equity firms replace the CEO during the hold period. Only 9% say they "rarely" replace. Of those replacements, 58% occur within the first two years. And 83% of PE firms report that unplanned CEO turnover lengthened the holding period and reduced returns.

Year two is not an accident. Year two is the point at which the gap between the executive's structural capacity and the role's load crosses the threshold where performance can no longer mask the deficit. The behavioral assessment conducted at deal close read the executive's performance at the point of maximum professional motivation — the CEO performing for the new owners, presenting the capabilities the board wants to see, operating at peak behavioral output. The assessment found what the methodology was designed to find: strong performance. The structural condition beneath the performance was not measured because the methodology does not measure it.

The cost is quantifiable. Entry multiples in 2026 are at record levels — 11.8x on average. There is over $1 trillion in U.S. dry powder under deployment pressure. External CEO hires have doubled from 18% to 33%. At these entry prices, with this much capital at risk, on CEOs who are increasingly hired from outside the organization and assessed through behavioral methodology that reads the presentation rather than the structural condition — the margin for error is effectively zero. A single CEO replacement at year two, with the associated disruption, extended hold period, and reduced returns, represents a loss that dwarfs the cost of independent structural measurement conducted at the point of hire.

The 41% perception gap documented in the 2026 data makes the structural limitation visible in the PE firm's own experience: 41% of PE firms rate their portfolio company's leadership team as "strong." Only 13% of the portfolio companies share that assessment. The gap between the PE firm's perception and the portfolio company's reality is 28 percentage points. That gap is the measure of what the current assessment methodology fails to detect. The PE firm reads the leadership's behavioral output and concludes "strong." The portfolio company lives with the leadership's structural condition and knows otherwise.

What Independent Measurement Looks Like in Practice

The assessment is remote. It does not require the executive to travel, to sit for a four-hour interview, or to be observed in a simulated environment. The measurement is conducted through a proprietary instrument that reads the executive's structural state through independent channels — channels that do not depend on the executive's conscious self-report, behavioral presentation, or capacity to manage the assessment environment. The session is brief. The output is an engineering report.

The report documents the executive's structural capacity, current load configuration, sustainability trajectory, and specific areas where the gap between load and capacity is widest. The report uses engineering vocabulary, not clinical vocabulary. The executive is not diagnosed. The executive is measured. The finding is structural: here is the system's current state, here is the system's trajectory, here is what the data indicates about the system's capacity to carry what the role requires over the timeline the deal thesis specifies.

The report goes in the file. It sits alongside the financial audit, the legal review, the technology assessment. It meets the standard the file requires: independent, instrument-based, documented, reproducible, conducted by a credentialed professional with no conflict of interest. The board, the operating partner, the deal team, the fiduciary attorney — each receives the finding in the format their role requires, calibrated to their decision framework.

Key person risk — the exposure created when the enterprise depends on a single individual whose capacity has not been independently measured — is the risk this assessment addresses. The cost of the assessment is a fraction of the cost of a single CEO replacement. The cost of a CEO replacement at year two — executive search, onboarding, lost momentum, extended hold, reduced returns — is typically measured in millions. The cost of independent structural measurement is measured in thousands. The economics are not close.

The Question the Board Has Not Yet Asked

Every board that commissions an executive assessment asks the same question: Is this person capable? The assessment answers from the behavioral data: here is what the executive presents, here is what the references report, here is how the executive scores on the personality profile. The board receives the answer and makes the decision.

The question the board has not yet asked — and the question that the governance standard of care is moving toward — is different: Can this person structurally sustain what we are about to ask of them? Not do they present as capable. Not do their references confirm capability. Not does their behavioral profile match the role requirements. Can the system carry the load, at the intensity the deal thesis requires, for the duration the hold period demands?

That question requires an instrument. It requires independent measurement. It requires a methodology that reads beneath the behavioral presentation to the structural condition the presentation conceals. Executive due diligence — the independent assessment of the human system the capital depends on — follows the same principle that drove the adoption of every other pillar: the recognition that value creation depends on a factor that cannot be verified without an independent instrument. The financial audit exists because boards learned, through costly experience, that financial statements require independent verification. The structural assessment of the key person exists for the same reason — because behavioral presentation, like financial reporting, is a produced output that can diverge from the underlying condition, and the divergence is not detectable without an independent instrument.

Every pillar of due diligence uses an independent instrument. The person the capital depends on deserves the same rigor.

Don L. Gaconnet, CSE III, is the founder of the LifePillar Institute for Structural Identity Sciences in Lake Geneva, Wisconsin. He conducts cognitive due diligence and structural identity assessment for private equity firms, boards, family offices, and fiduciary counsel. His published research on structural assessment methodology is archived on SSRN (Author ID: 7657314) and OSF (ORCID: 0009-0001-6174-8384). He maintains professional independence with no search firm affiliations.

For inquiries: dongaconnet.com