What is a 90-day Diagnostic? A practical guide for growth-stage boards.

A 90-day Diagnostic is a quarter-long advisory engagement that reads the whole commercial and operating model of a growth-stage B2B SaaS business against evidence. Twenty questions across four operating components. Written diagnostic, target operating model, board pack. Hand-off in the final week.

The Diagnostic exists because boards regularly reach a moment where the honest question is not "which lever do we pull next" but "is this business ready to scale at all". A Sprint cannot answer that. The whole picture has to be read. The evidence has to be triangulated. The verdict has to be written down.

This guide is for new CEOs in their first hundred days, PE operating partners running portfolio reads, and Chairs of growth-stage boards deciding whether to invest in a rebuild.

What a 90-day Diagnostic actually is

The Diagnostic is the deeper cousin of the Growth-Stage TOM and Five Questions Diagnostic tools. Where the tools give a self-assessment a leadership team can run in half an hour, the Diagnostic is Andrew's independent read of the same underlying question at the depth a board decision needs.

The Diagnostic uses the same twenty-question spine as the TOM. That means the framework is public, testable, and grounded in the same operating logic Andrew has used across four exits. The board is not paying for a bespoke methodology invented for the engagement. It is paying for the evidence, the interviews, the interpretation, and the written verdict.

The output is written. A sixty to ninety-page diagnostic paper, structured for a board reader. A separate target operating model, sized for the executive team. A board pack that a Chair can take straight into the next board meeting. All three delivered in the final week.

The framework is public. The verdict is what the board is paying for.

What a 90-day Diagnostic is not

The engagement is misread often enough to need a definition by exclusion.

1. Not a management consulting exercise. No delivery team. No hundred-slide deck. Andrew runs the Diagnostic personally. The interviews, the analysis and the writing are all his. That is why the read is defensible.
2. Not an operating engagement. The Diagnostic reads the business. It does not install the rebuild. When the diagnostic surfaces work the executive team does not have the seat to close, the honest follow-up is a Fractional CGO engagement, not more diagnostic time.
3. Not a strategy report. Strategy work asks "where should we go". A Diagnostic asks "is the current operating model built for where we already are, and what evidence supports that read". The two questions overlap but the shape of the answer is different.
4. Not a scorecard. Traffic-light reads on their own are not board-ready. Every Red or Amber comes with evidence, interpretation and a working recommendation. The verdict is the paper, not the colour.
5. Not a substitute for the tools. Many boards commission a Diagnostic after running the free tools first. The tools give the executive team a working self-assessment. The Diagnostic gives the board an independent read of the same territory at the depth an outside interpretation provides.

The four operating components

The Diagnostic reads the business across four operating components. Each carries five of the twenty questions. Each question gets a traffic-light read (Green, Amber, Red), an evidence summary, and a working recommendation.

Not every business needs all four read at the same depth. Where a component is clearly strong, the Diagnostic confirms it in a paragraph and moves on. Where a component is the actual gap, the Diagnostic goes deep, brings evidence, and writes the recommendation with the same weight the CEO would need to act on it.

When to commission a Diagnostic

Five patterns show up in practice.

1. New CEO in first hundred days. The Diagnostic runs alongside the new CEO's own listening exercise. By day one hundred the CEO has an independent whole-business read to test their instincts against. Often the most valuable use of the engagement: two independent reads that converge or diverge at specific, argued points.
2. PE ops partner running a portfolio read. One asset in the portfolio is not tracking to plan. The Diagnostic answers whether the plan was wrong, the execution is wrong, or the operating model is not built for the next stage. Delivered as a board-facing paper the ops partner can take to the portco Chair.
3. Chair scoping a rebuild. The board suspects the business needs restructuring but wants an evidence base before the conversation. The Diagnostic provides it, in writing, with the risks the recommendation sits on stated openly.
4. Pre-fund raise or pre-exit. Twelve to eighteen months out. The commercial and operating story needs to be defensible before it lands in front of a lead investor or a strategic buyer. The Diagnostic reads the story cold and rewrites what will not survive contact.
5. Post-acquisition integration. Two commercial motions collided in the deal. The Diagnostic reads both against the same twenty-question spine and produces one target operating model, plus the sequence in which the collision points get resolved.

When not to commission a Diagnostic

Three cases, all real.

1. When the question is narrow enough for a Sprint. If the board question fits in a single sentence and needs a two-week read, commission a Sprint. A Diagnostic is the wrong instrument for one question. It is the right instrument for twenty.
2. When the executive team is mid-transition. If the CEO is leaving, or the CRO is being replaced, the Diagnostic reads a business that will not exist in six months. Wait until the transition has settled, or commission a Sprint to answer one urgent question in the interim.
3. When the board is not prepared to act on the answer. A Diagnostic that produces a defensible read of a rebuild the board is not willing to fund is money wasted twice. If the board is not ready to move on findings, the honest first step is a governance conversation, not a Diagnostic.

How the Diagnostic runs

Thirteen weeks. Three phases. Two interim check-ins.

1. Weeks one to four. Immersion. Data room review. Interviews with the executive team and up to ten named people across commercial, delivery, product and finance. Customer or partner interviews where the scope includes them.
2. Weeks five to nine. Analysis. Each of the twenty questions gets a working answer. Evidence is triangulated. Interim read to the CEO or Chair at week six. Second interim at week nine.
3. Weeks ten to twelve. Writing and hand-off. The diagnostic, the target operating model, the board pack. Hand-off call with the CEO or Chair at week twelve. Board presentation available in week thirteen if the board meeting calendar allows.

The engagement is designed to sit alongside operating cadence, not replace it. Executive interviews are scheduled around the operating rhythm. The heavy analysis weeks are Andrew's, not the team's. The team keeps running the business while the Diagnostic reads it.

What you get

Three named deliverables. Written and hand-off in the final week.

1. The written diagnostic. Sixty to ninety pages. Structured for a board reader. Twenty questions answered with Green, Amber or Red, evidence, and working recommendation. Written in the same voice as the tools and the field guides. Not a slide deck. A written paper.
2. The target operating model. A separate document sized for the executive team. Not aspirational architecture. A picture of the operating model the business needs at the next stage, drawn from the same evidence base as the diagnostic itself.
3. The board pack. Twelve to twenty slides drawn from the diagnostic. Sized so a Chair can take the pack straight into the next board meeting. Speaker notes in the file.

Where the question needs it, the written diagnostic is accompanied by an appendix of the evidence base. Interview notes, data reviewed, source documents cited. That appendix is added when the board needs to see the working, not delivered by default.

How Andrew works during a Diagnostic

The method has four defining features.

Public framework. The Diagnostic uses the twenty-question TOM spine that anyone can read at ortent.co/tools/operating-model. The executive team can read the framework the day the engagement is commissioned. That transparency is deliberate. The board is not paying for a proprietary methodology. It is paying for the read.

Triangulated evidence. Every Red or Amber has to survive triangulation across the executive interview set, the data room, and where relevant, a customer or partner interview. Single-source findings do not make it into the written diagnostic. If the evidence is only in one place, the paper says so.

Interim reads. Two written interim reads land during the engagement: one at week six, one at week nine. The interims are not full drafts. They are working notes on where the evidence is pointing. The CEO or Chair can push back at the interim, and the direction of the deep work adjusts. That is what the interim is for.

Written recommendations with the risks stated. Every Red gets a working recommendation, and every recommendation states the risks it sits on. If the recommendation depends on a hire that has not been made, the paper says so. If the recommendation depends on a market condition that could change, the paper says so. Boards notice which advisors write the risks down and which do not.

Diagnostic vs Sprint vs Fractional CGO

Three engagement shapes, three different answers to "what is on the table".

Sprint. Two weeks. One question, one board-ready written answer. Best when the board or the CEO has a specific decision to make and needs an evidence-based read before the meeting. Fixed scope, fixed fee.

90-day Diagnostic. One quarter. Twenty questions answered against evidence, across the four operating components of the business. Best when the board is asking whether the business is scale-ready at all, or when a new CEO needs a whole-business read in their first hundred days.

Fractional CGO. Ongoing. Part-time senior commercial leadership inside the executive team. Two days a week, three-month minimum. Best when the Diagnostic has surfaced a commercial architecture gap the executive team does not have the seat to close.

Sprints and Diagnostics are one-off engagements. Fractional CGO is an operating seat. In practice, a Diagnostic sometimes leads into a Fractional CGO engagement, and sometimes leads into an Advisory retainer. Neither transition is expected, but both are common and honest when the work justifies it.

What comes after

Three common patterns.

1. The board runs the plan. Diagnostic hands off, executive team owns the follow-through, Andrew stays available on retainer as Advisory. Monthly working sessions with the CEO. Board-pack review before every board meeting.
2. The Diagnostic becomes a Fractional CGO engagement. When the diagnostic surfaces a commercial architecture gap the executive team does not have the seat to close, Andrew steps in as Fractional CGO to install the rebuild. The Diagnostic is credited against the first month of the Fractional engagement in that case.
3. The Diagnostic is the whole engagement. The board takes the read, acts on it, and returns for the next Diagnostic in twelve to eighteen months. Some of the most valuable Diagnostics are the ones that confirm the business is on track and identify the one or two things worth watching.

What to look for when commissioning a Diagnostic

Six things a Chair, CEO or PE ops partner should insist on when commissioning any quarter-long advisory diagnostic, from anyone.

1. A public framework, not a proprietary black box. If the methodology is only visible after the invoice is paid, the board cannot pressure-test the read. A framework anyone can read in advance builds defensibility into the engagement from day one.
2. A named senior operator doing the work personally. Twelve weeks is enough time for a delivery team to onboard and deliver, but the depth of the read comes from a single operator holding the whole picture. If the pitch is "I take the intake call and my team runs the analysis", the read gets thinner as it goes.
3. Interim reads at week six and week nine. No interim reads means no chance for the CEO to correct the direction of the deep work. A Diagnostic that only surfaces at week twelve is too late to shape.
4. Triangulated evidence. Ask, before commissioning, how single-source findings are handled. If they are treated as findings, the read will overreach. If they are noted as unconfirmed and reported separately, the read is honest.
5. Written recommendations with risks stated. Every board-ready recommendation sits on assumptions. A Diagnostic that reads as clean and unqualified has not done the work.
6. Willingness to write "on track" as a finding. Confirmation is a legitimate output. Any advisor unwilling to write it should not be commissioned.

Red flags when commissioning a Diagnostic

Four flags that suggest the engagement will not land.

1. The proposal promises a hundred-slide deck. A quarter-long Diagnostic that ends in a hundred slides has bought quantity in place of quality. The primary artefact should be a written paper, not slideware.
2. The scope keeps expanding before kick-off. If the framework, the interview set or the deliverables change shape between the intake conversation and kick-off, the twelve-week clock is already broken. Ask for the intake note to be re-signed.
3. The advisor cannot state a working hypothesis by week four. Immersion should produce a working point of view early, refined by the deep work. An advisor still gathering opinions at week seven is running out of runway.
4. The delivered paper reads as consultancy-safe. If every finding is Amber, every recommendation is qualified into meaninglessness, and no risk is written down, the paper has not done the work. A board-ready Diagnostic has a spine.

What people say

// COMMERCIAL PARTNER MINDSET ENDORSEMENT

"Andrew is one of the few SaaS leaders I've worked with who genuinely understands how to build commercial relationships at the intersection of life sciences and software. He thinks like a partner, not a vendor, which is exactly what makes the work move."

Dr Joanne M. Hackett VP, Global Head of Health System Services · IQVIA LinkedIn →

Diagnostic services from Ortent

Ortent Advisory is led by Andrew Wyatt. Thirty years in B2B SaaS. Four exits: Lotus to IBM ($3.5B), Paragon Software to Phone.com ($500M), Apertio to Nokia ($240M), Clearswift to Lyceum Capital ($50M). Most recently Chief Growth Officer at Sapio Sciences and Sigmatic Sciences. Before Sapio, Chief Operating Officer at Lumeon.

Ortent Diagnostics are commissioned by new CEOs in their first hundred days, PE operating partners running portfolio reads, and Chairs of growth-stage boards deciding whether to invest in a rebuild. Between £5m and £30m ARR is the usual band, though earlier and later stages are workable when the question is well-shaped.

Diagnostics are always run by Andrew personally. There is no delivery team. The intake, the interviews, the analysis, the writing, and the hand-off are all his. That is the point.

Engagements start with a fifteen-minute call to test fit. If there is a match, the next step is a written intake note covering the framework, the interview set, the interim schedule and the hand-off date. No obligation to commission until the intake note is signed.

FAQs

How does a 90-day Diagnostic compare to a Sprint?

A Sprint answers one question in two weeks. A Diagnostic reads the whole commercial and operating model in a quarter and produces twenty answered questions across four components. Different shape, different price, different audience. Commission a Sprint when the board has a specific question. Commission a Diagnostic when the board is asking whether the business is scale-ready at all.

Can the Diagnostic run while the executive team is delivering the current plan?

Yes. The Diagnostic is designed to sit alongside operating cadence, not replace it. Executive interviews are scheduled around the operating rhythm. The heavy analysis weeks are Andrew's, not the team's.

Do we have to use the TOM framework?

Yes, and the reason is transparency. The framework is public at ortent.co/tools/operating-model. Anyone on the executive team or the board can read it in advance. The Diagnostic is the evidence-gathering and the verdict, not a proprietary black box.

What if the answer is "there is nothing wrong"?

The Diagnostic says so, in writing, with evidence. That is a defensible read for a board and an investor. Confirmation is a legitimate output. A fabricated finding is not.

Can the output be sanitised for external readers?

Yes. The board pack is designed to be the default external-facing artefact. The written diagnostic is CEO or board only unless we agree otherwise at intake.

What does a Diagnostic cost in the UK in 2026?

Fixed-fee, quoted at intake. Typical range for a quarter-long Diagnostic sits between £35,000 and £55,000, moving higher when customer or partner interviews or international coverage are in scope.

How is the Diagnostic priced?

Fixed fee, agreed at intake. Price depends on the size of the business, the sectors served, whether customer or partner interviews are in scope, and whether the target operating model needs to include international expansion.

What is the relationship to the tools set?

The interactive tools are free self-assessments a leadership team can run without commissioning anything. Many boards commission a Diagnostic after running the tools and wanting an independent read of the same territory at the depth an outside interpretation provides.

The bottom line

A 90-day Diagnostic answers whether the business is scale-ready at all. Twenty questions. Four components. Written down. Interim reads at week six and week nine. Board-ready paper by week twelve. If that is the shape of the read your board needs, commission a Diagnostic. If the question is narrower, commission a Sprint. If the answer will need installing rather than deciding, the honest follow-up is Fractional CGO.