Fractional data science jobs · Head of data science · Data scientists

Fractional data science jobs · hire a fractional head of data science, or hire one for good

Fractional data science jobs are data science roles held for part of the week.

Most are for a head or director of data science who leads the models and the people who build them; some are for a senior data scientist who builds the models.

To hire a fractional head of data science, decide which you need and which decision the models should improve.

We recruit fractional, interim, part-time, temporary and permanent data and technology leaders.

On every brief we send a shortlist of 3–5, each with pay or day rate, availability and IR35 position set out, after five-stage vetting.

Looking for work?

Technology and data leadership roles are on the board below.

Brief us on a data science hire →See the roles

How a brief runswhat we undertake

01Brief30-MINUTE SCOPING CALLDay 0
02Shortlist of 3–5VETTED · RATE BENCHMARK · IR35After the brief
03InterviewsYOU MEET THE SHORTLISTYour diary
04Scoped startFIRST-MONTH OUTCOMES AGREEDYou set the date
05Fractional, interim and permanentIR35 POSITION SET OUTOn every brief

Shortlist3–5

3–5

Shortlist · with pay or day rate, availability and IR35 set out

Vetting · stages before a candidate reaches you

15 minutes · video or phone

Book 15 minutes to hire a fractional head of data science

Tell us the scope and the days a week. We come back with head of data science candidates, their day rates and availability.

0115 minutes, video or phone
02We scope the role and the days a week
03A shortlist of 3–5 after the call
04Fractional, interim and permanent briefs

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Pick a day that suits · live availability

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On the board · last 3 months

Data and technology roles jobs on the board

1 on the board · 0 confirmed open

FractionalSyndicated
Fractional IT Director – Technology & AI (FTC)
Flat Iron · London
est £1,000/day2 d/wk

Browse every role on the board →

Technology and data leadership roles on the board

Fractional Quest is a fractional recruitment agency: send a head of data science brief and we come back with a shortlist of three to five vetted candidates.

01/ the role

Fractional data science jobs: what the work is

The government’s Digital and Data capability framework describes data science as a broad and fast-moving field spanning maths, statistics, software engineering and communications.

In practice it means using data to predict, classify or optimise something the business cares about: demand, pricing, churn, fraud, risk, or which customer to call first.

Fractional data science jobs put someone senior on that work for part of the week.

Two kinds of seat

The leadership seat sets direction: which problems are worth modelling, which tools and methods the team uses, how models are tested, released and watched, and who is hired.

The individual contributor seat builds: cleans the data, writes the code, trains and validates the models and explains the results.

A small company’s first senior data hire often does both.

Say which one you want to hire.

When a business brings one in

The usual moments: a first model the business wants to rely on, a team of analysts or junior data scientists with nobody senior to review their work, a model already in production that nobody trusts or can explain, or an investor or buyer asking how the numbers are produced.

None of these needs a full-time executive on day one.

For a view of the field beyond your own business, the Alan Turing Institute is the UK’s national institute for data science and artificial intelligence, and the ONS’s Data Science Campus publishes data science work for the public good.

02/ scope

How to hire a fractional head of data science

1. Start from the decision

Name the decision the models should improve, who makes it today, and how you would measure a better one.

A head of data science hired to “do AI” with no decision attached tends to produce demonstrations rather than results.

2. Check the data comes first

Models inherit the quality of the data under them.

If nobody owns data strategy, governance and quality, hire a fractional chief data officer first, or alongside.

If the gap is the platform and the engineering team, hire a fractional CTO.

For the wider data leadership market, see fractional CDO jobs.

3. Test the leadership, not only the maths

The framework says a head of data science has complete oversight of data science in the organisation: sets direction, builds capability, oversees resourcing, budgeting and outputs, and leads on ethics.

Ask candidates for a model they took into production, how it was monitored and what happened when it drifted.

Professional recognition helps: the Royal Statistical Society’s Advanced Data Science Professional certificate recognises experienced data scientists against the Alliance for Data Science Professionals’ standards.

Treat it as evidence, not a requirement.

To write the brief at the right level, the SFIA framework, an internationally adopted skills framework for digital work, covers data science among its skills.

What we do on the brief

We send a shortlist of 3–5 candidates, each with pay or day rate, availability and IR35 position set out.

Every candidate goes through our five-stage vetting first.

03/ the week

How a week divides.

Part of a week is the point of the model: the days you buy are yours, the rest of the week goes to other clients. Move the days a week and the week redraws.

Days a week for your company2 days

Your companyAnother clientA third client

Mon

Tue

Wed

Thu

Fri

Illustration only: one way a fractional head of data science’s week can divide at 2 days a week for you. Each block is half a day.

04/ the board

What the board holds.

A read of the roles on the board on this page, counted as they stand: how each is engaged, whether the posting gives the days and the rate, and where the work happens.

On this board, last 90 days · 1 role · Data and technology roles

Engagement

Fractional1

Days a week

Stated in the posting1
Not stated0

Day rate

Verified rate0
Estimated (est)1
Rate not stated0

Work arrangement (as the job feed classifies it)

Remote0
Hybrid1
On-site0

Newest posting on the board: 8 Oct 2026.

05/ the route

Fractional, interim or permanent?

Four taps. The answer names the route for the seat and the page that covers it.

How much of the week does the work fill?

Is there a fixed end or a programme?

Does the seat sit on the board for years?

Is the need now, or can it wait for a search?

The route · Fractional

A fractional head of data science.

The work fills part of the week, so buy the days it needs.

A fractional head of data science holds the seat on agreed days for as long as the seat is needed, and works for other clients on the rest.

The fractional head of data science roles on this page Talk it through

06/ comparison

Scientist, head or chief officer: three data seats compared

Three seats that share data but do different work. Choose by what the person will own.

Data scientistHead of data scienceChief data officer

OwnsBuilding and validating models, analysis and codeWhich problems are modelled, methods, standards, the teamData strategy, governance, quality and architecture

Typically reports toA lead or head of data scienceThe CDO, CTO or an executiveThe chief executive or another executive

Hands-onFullyPartly, more so in a small teamRarely

SuitsA defined modelling job with direction already in placeA business that needs models it can rely on and someone to run the workA business whose data is not yet trusted or governed

07/ vetting

How we vet every candidate

What we undertake on every brief, before a candidate reaches you.

01
Qualification screen
Verify head of data science tenure, sector context and stage fit.
SOURCING
02
Mandate fit
Match to your situation — stage, board dynamics, timing.
MATCHING
03
Reference deep-dive
We take references ourselves, from recent past clients — real outcomes, not titles.
VERIFY
04
Shortlist
Three to five candidates with day rate, availability and IR35 position set out.
SHORTLIST OF 3–5

08/ fractional data scientist

Fractional data scientist: an individual contributor, a lead, or both?

Many roles advertised as fractional data scientist are hands-on: a senior person who builds the models, writes the code and presents the findings, a few days a week.

That is an individual contributor seat, whatever the day rate.

Others are the lead seat under a smaller title, and in a start-up the first data scientist is often both.

The government framework draws the line usefully.

Its data scientist level works independently and develops complex solutions; its principal data scientist is described as a leader of data science, quite often with responsibility for managing and developing teams; its lead and head levels set direction and build capability (DDaT framework).

Work out which level your problem needs before you brief.

The individual contributor seat also raises sharper employment questions.

Someone embedded in your team, whose manager decides what they work on and how, looks more like an employee on GOV.UK’s indicators.

Where they work through their own company, the off-payroll rules apply: a medium or large client makes the determination, and status turns on how the engagement runs.

We recruit the leadership seat, and the board below lists leadership roles.

09/ head of data science vs cdo

Head of data science vs chief data officer: the models, or the data under them?

A chief data officer owns how the organisation manages and uses its data: the data strategy, governance and quality, the architecture and lawful use.

The full list of duties is on what does a chief data officer do.

A head of data science owns what is built on that data: the models, the experiments and the people who run them.

Decide which to hire first by where the weakness is.

If the data is not yet trusted, a head of data science spends the engagement cleaning it and the models wait; start with the chief data officer.

If the data is sound and the gap is turning it into decisions, a head of data science fits.

Some businesses need both on a few days each, with the head of data science reporting to the CDO.

For the chief data officer seat, and for the head of data and healthcare data variants, see fractional chief data officer jobs.

10/ models and people

When models make decisions about people: what the seat answers for

A pricing, credit, hiring or fraud model that scores people brings data protection with it.

The ICO’s guidance on AI and data protection covers fairness and statistical accuracy as well as lawfulness and transparency; the ICO notes it is under review after the Data (Use and Access) Act.

That Act opens up the lawful bases for significant automated decisions about people, provided appropriate safeguards are in place, but not for special category data.

The government’s Data and AI Ethics Framework was written for the public sector, but its principles for the responsible development, procurement and use of data and AI are a sound checklist for any team.

A head of data science should be able to show where fairness and accuracy are tested in the release process, and who signs a model off.

11/ questions

Fractional data science jobs FAQ

The questions people ask before bringing in a fractional head of data science.

Data science roles held for part of the week. Most are for a head or director of data science who leads the modelling work and the team; some are for a senior data scientist who builds the models. Either way the business gets senior data science without a full-time appointment.

Name the decision the models should improve and how you would measure it. Check the data is trusted first; if not, hire a fractional chief data officer first or alongside. Then ask each candidate for a model they took into production and how they monitored it, and agree the days and reporting line in writing.

The day rate times the days worked. We set out each candidate’s day rate on the shortlist rather than quote a market band: we have not found a published head of data science rate we can source.

Usually, yes: director of data science and head of data science are two titles for the person who leads data science in a business. Some larger organisations put a director above several heads. Judge the seat by what it owns and who it reports to. For director of data science against a chief data officer, see fractional chief data officer jobs.

A data scientist who works for a business part of the week. Many are hands-on individual contributors who build the models themselves; others lead a small team. In a start-up the first data scientist often does both. Decide which you need before you brief.

A chief data officer owns the data itself: strategy, governance, quality and architecture. A head of data science owns what is built on it: the models and the team that builds them. If the data is not trusted, start with the chief data officer; see what does a chief data officer do.

It depends on how the engagement runs. A data scientist embedded in your team and directed day to day looks more like an employee; one delivering a defined piece of work with their own methods looks less so. For a medium or large client the client decides, under HMRC’s off-payroll rules. See our IR35 guide.

Usually a quantitative degree and a track record of models in production. Professional recognition such as the Royal Statistical Society’s Advanced Data Science Professional certificate is useful evidence. Weigh it alongside what the candidate has shipped and how they led the people who shipped it.

Book 15 minutes · shortlist of 3–5

Bring the brief. We architect the team.

A shortlist of 3–5 with day rate, availability and IR35 position set out, after five-stage vetting.

Book a call →Submit a brief