Insights Hub

The research behind the system. The ongoing thinking that shapes it.

23 founder interviews · 20+ co-founder breakup case studies · ongoing field research

Most startup advice about co-founders is generic. Trust each other. Communicate well. Have hard conversations early. But which conversations? About what? When do these problems actually surface?

This system was built from founder stories — not hypotheses. The patterns below emerged from 23 in-depth case studies and 250+ founder interviews across every team archetype.

The same patterns keep appearing

Across 23 case studies — siblings, spouses, friends, strangers — the same 7 dimensions surfaced as breaking points. Different industries, different stages, same fracture lines.

Early signals get ignored

Most founders could identify yellow flags in retrospect. They just didn’t have language for them at the time, or assumed “we’ll figure it out later.” Language is the intervention.

Legal documents don’t prevent breakups

Every failed partnership we studied had proper legal agreements. The problem wasn’t documentation — it was unexamined assumptions and avoided conversations that the documents never addressed.

Awareness isn’t enough

Knowing “we should communicate better” doesn’t help. Founders need structured frameworks for specific conversations — about equity, roles, decision rights, and what happens when things go wrong.

About this research

Conducted by Alterrell Mills (Harvard BA, Harvard Business School MBA) — 15+ years at Fortune 100 companies focused on organizational dynamics and team dysfunction patterns. The Mills Mirror is the diagnostic infrastructure built from what that research revealed.

Findings are directional insights from qualitative research, not statistically representative data. All case studies are anonymized.

Ongoing thinking

The research is a foundation. The Substack is where it continues — new patterns, field observations, and analysis as the work develops. Free to read and follow.

Follow on Substack →

The research exists in two forms. The Insights Summary gives you the frameworks and patterns. The Casebook shows them in motion through 23 anonymized founder stories.

Insights Summary

The Anatomy of Founder Breakups

Based on 23 founder interviews, this 11-page report distills the warning signs, intervention points, and counterintuitive insights that appear before partnerships break down. Includes the 7 most common red flags, stage-by-stage interventions, and reflection questions for current partnerships.

Casebook

The Founder Breakup Casebook

The companion volume. Where the Insights Summary distills patterns, this one shows them in motion — 23 anonymized case studies across five founding archetypes, each with context, story, analysis, and a distilled lesson. Partners & Spouses, Family & Siblings, Friends to Founders, Professional Pairings, Solopreneurs.

Best value

Complete Founder Breakup Bundle

Both reports. Start with the frameworks in the Insights Summary, then go deeper through the Casebook stories. The two are designed to be read together — one gives you the map, the other shows you the terrain.

$99 $118

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Insights Summary is for

Early-stage founders vetting a potential partner, accelerator staff and mentors working with new teams, investors assessing people risk before a bet.

Casebook is for

Founder coaches and accelerator managers, early-stage VCs studying team dynamics, founders who process through story rather than frameworks.

This is living research. The system improves as more founder stories come in — more archetypes, more edge cases, more patterns we haven’t seen yet.

If you’ve experienced a co-founder breakup or a partnership that came close to dissolving, your story helps future founders navigate with clearer maps. All contributions are anonymized before being used in any research or publication.

What we’re looking for

→Partnerships that dissolved or came close to dissolution

→The friction points and early signals you noticed (or missed)

→What you wish you’d known or done differently

→The moment things became unfixable — and when the signs first appeared

All stories are anonymized. Direct identifiers — names, company names, locations, investor references — are removed or altered before any use. Your story contributes pattern data, not identifying detail.

From the Substack

Longer-form thinking published on Substack — co-founder breakup stories, decision frameworks, and patterns from the research. Free to read and follow.

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