Why Your Health System's Best People Leave After a Merger — And What One Pediatric System Did Differently

I got the call on a Tuesday.

A pediatric health system — 250 beds, strong community reputation, well-respected medical staff — was eighteen months into a system integration. On paper, everything was proceeding according to plan. The governance structure had been ratified. The financial models were aligned. The IT migration was on schedule.

And their best clinicians were leaving.

Not dramatically. Not with resignation letters slammed on desks. Quietly. A surgeon who'd been there fourteen years accepted a position across town. A department director who'd built her program from scratch stopped showing up to leadership meetings, then stopped showing up entirely. Three hospitalists, the ones everyone relied on for weekend coverage, gave notice within six weeks of each other.

When I asked the CEO what happened, he said something I've heard dozens of times: “We did everything right. I don't understand why the culture fell apart.”

He had done everything right, strategically. What he hadn't done was prepare the organization to receive the change before he executed it.

That's the gap almost every health system falls into. And the research tells us exactly how expensive it is.

The Numbers Nobody Wants to Read at a Board Meeting

Here's what the data says about what happens when organizations skip cultural readiness:

According to a Harvard Business Review analysis cited by Lakelet Capital, the failure rate for mergers and acquisitions falls between 70 and 90 percent. That number has improved in recent years, some studies now show success rates in healthcare hovering around 65 to 70 percent — but the reason for the improvement is telling. The organizations that succeed are the ones investing in cultural alignment and employee engagement, not just synergy capture and operational integration.

McKinsey found that nearly 50 percent of mergers fail to meet expectations specifically due to organizational issues,  cultural differences and operating model misalignment. PwC's research reinforces this: 65 percent of acquiring companies reported that cultural issues hampered their post-merger operations.

And the human cost? MRINetwork's data shows that the average employee turnover rate after a merger is 47 percent in the first year. That number climbs to 75 percent within three years. Roughly 30 percent of that turnover is attributed directly to cultural mismatch, not compensation, not geography, not career advancement. Culture.

In healthcare, the consequences of that turnover are not abstract. A BMJ study of over 236,000 nurses and 41,800 senior physicians found that increases in staff turnover were associated with statistically significant increases in patient mortality risk within 30 days of admission. We are not talking about productivity metrics. We are talking about patient lives.

The Leadership Transition Problem Compounds It

Mergers don't happen in isolation. They almost always trigger leadership transitions,  and those transitions carry their own failure rate.

Research from the Center for Creative Leadership and LeadershipIQ shows that 40 to 50 percent of senior executives fail within their first 18 months. Other estimates put executive failure rates as high as 60 percent for U.S. executives. McKinsey's 2014 Leadership Transitions paper confirmed the failure rate has held at 40 percent for over 15 years.

In healthcare specifically, the churn is accelerating. Challenger, Gray & Christmas reported that 78 hospital CEOs left their positions in the first seven months of 2025,  a 15 percent increase over the same period in 2024. And ACHE research shows a cascading effect: 52 percent of COOs leave within one year of a CEO transition. Forty-two percent of CFOs follow. Thirty-seven percent of HR officers.

So picture this: you've just completed a merger. The incoming CEO is trying to establish credibility. The COO is watching the door. The medical staff is skeptical. The frontline has already decided,  silently, collectively,  whether they trust what's happening. And nobody has stopped to assess whether the organization is actually ready for what it's being asked to absorb.

This is the moment that determines whether your strategic plan becomes an institutional achievement or a case study in preventable failure.

What the Pediatric System Did Differently

Back to that Tuesday phone call.

The pediatric system had done what most organizations do: they'd built the integration plan from the top down. Board alignment, financial modeling, operational workstreams, communication templates. All of it, technically sound.

What they hadn't done was go into the units. They hadn't asked the charge nurse on the night shift what she was afraid of. They hadn't surfaced the fact that two department directors,  both critical to the integration, hadn't spoken directly in over four months. They hadn't discovered that a group of thirty clinicians had collectively decided, without a single formal conversation, not to adopt the new documentation protocol.

Nobody was sabotaging the integration. They were protecting themselves from it.

When we came in, we didn't start with a new plan. We started with The Shift Method™ — our organizational readiness framework that intervenes before execution, not after failure.

We started with Surface: Going into the rooms nobody had been asking about. Not with a survey. With presence. Listening to what people were actually saying to each other when leadership wasn't in the room. What we found wasn't resistance. It was grief. The organization was mourning a version of itself that no longer existed, and nobody had given it permission to do that.

Then Release. The system was carrying three legacy initiatives that had been functionally dead for over a year but had never been officially ended,  because the previous CEO had championed them. Every leader knew they weren't working. Nobody wanted to be the one to say it. We created the space to name what needed to end so the organization could stop spending energy protecting things that no longer served its mission.

Then Reconnect. The two department directors who hadn't spoken? It wasn't a personality conflict. It was a structural ambiguity,  neither one knew who owned what in the new integrated model, and rather than risk a confrontation, they'd simply stopped communicating. Once we facilitated the conversation, they rebuilt alignment in a single afternoon. They didn't need mediation. They needed someone to put them in the same room with a clear question.

Then — and only then — Rise. When the organization moved into execution, it moved together. The documentation protocol that thirty clinicians had silently rejected? After the readiness work, adoption hit 94 percent within 60 days. Not because the protocol changed. Because the people carrying it forward finally trusted the process that brought it to them.

The Difference Is Readiness, Not Strategy

The Corporate Executive Board (now Gartner) found that successful leadership transitions result in a 90 percent higher likelihood that teams will meet their three-year performance goals. Ninety percent. That's the performance gap between an organization that prepared and one that assumed preparation wasn't necessary.

Baker Tilly's research on organizational readiness assessments reinforces the point: waiting to address obstacles until the change is already in motion reduces confidence across the organization and can delay or entirely derail the transformation, at a point where significant resources have already been invested, making course correction exponentially harder.

Here's what I know after twenty years inside academic health systems: the strategy is almost never the problem. I have watched brilliant, well-funded, board-supported strategic plans die quiet deaths, not because the plan was wrong, but because the organization wasn't ready to receive it.

Cultural readiness is not a soft skill. It is not a nice-to-have. It is the infrastructure that determines whether your investment in change produces a return or becomes a write-off.

Three Questions Every Board Should Ask Before Approving a Transformation

If your health system is entering a merger, a leadership transition, or a major strategic initiative, these three questions will tell you more about your likelihood of success than any financial model:

Have we gone into the units — not with a survey, but with presence — and asked the people who carry this organization what they're actually experiencing right now?

Is there anything this organization has silently agreed to tolerate that is consuming energy, eroding trust, or blocking forward motion?

Do the people who must carry this strategy forward believe in it — or are they simply compliant?

If you can't answer those questions with confidence, you're not ready. And executing before you're ready doesn't make you decisive. It makes you expensive.

Dr. Adrianne Ross is the Founder and Principal of Pheno Health Group and the creator of The Shift Method™, a facilitated organizational readiness framework for health systems navigating transformation. She has spent twenty years leading operations inside academic health systems, including serving as President & COO at the University of Vermont Health Network. She works with health systems, academic medical centers, and family offices to solve what others can't — and build what's next.

Contact Dr. Ross → adrianne@phenohealthgroup.com

Sources Referenced in This Article

• Lakelet Capital / Harvard Business Review — M&A failure rate analysis (70–90%)

• McKinsey & Company — Merger expectation failure due to organizational issues (~50%)

• PwC — Cultural issues hampering post-merger operations (65%)

• MRINetwork — Post-merger employee turnover rates (47% year one; 75% within three years; 30% culture-attributed)

• BMJ — Nurse and doctor turnover associated with increased patient mortality risk (NHS acute trusts, England)

• Center for Creative Leadership / LeadershipIQ — Executive failure rates within 18 months (40–50%)

• Industry estimates — U.S. executive failure rates (up to 60%)

• McKinsey Leadership Transitions (2014) — 40% failure rate sustained over 15 years

• Challenger, Gray & Christmas — 78 hospital CEO departures in first 7 months of 2025

• American College of Healthcare Executives (ACHE) — C-suite cascading turnover following CEO departure (52% COO, 42% CFO, 37% HR officer)

• Corporate Executive Board (Gartner) — Successful transitions and 90% higher likelihood of meeting 3-year performance goals

• Baker Tilly — Organizational readiness assessment research