The Diary of a CEO - Audited

Every full episode since October 2020, measured: what changed, when, and by how much.

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532full episodes

5.9years of uploads

532thumbnails

24topic categories

6 years in one image

Each block is one full episode, in publication order from the first upload at the top left. Early rows show a guest alone against black; from 2023 the host appears on the right; from 2025 the frame is brighter with more faces. Click any thumbnail to see its measurements.

532 full episodes; the host appears in 17% of thumbnails in the first year of uploads and 94% in the most recent year.

Explore every episode with filters →

The channel year by year

A systematic sample of each year's thumbnails (every nth episode, not hand-picked) with that year's measures alongside. Shares are of full episodes. The Packaging Intensity Index is a 0–100 composite explained further down.

2020

Nine episodes in ten weeks after the channel's relaunch at episode 53. Two thirds are about the mind (psychology, mental health, personal development); a fifth are business. Every thumbnail carries lowercase text; the host is in two of nine.

2021

48 episodes. Business, entrepreneurship and career reach 31% of primary topics, their highest full-year share, and the third quarter is the only quarter in the channel's history in which they pass half. Guests are celebrities, founders and authors. The host is in 27% of thumbnails.

2022

94 episodes and the highest raw share of founder titles. Business peaks at 42% in a 40-episode window in June and then falls. Health is 18%. Archived captures show that this year's hits were later re-thumbnailed twice, so the lowercase look measured here is itself a late-2022 re-skin for at least the biggest episodes.

2023

The first statistical break, late January. The host enters the frame: 60% of thumbnails in the first quarter, 100% by the third. The health family reaches 40% of episodes, doctors and academics arrive as a guest class, titles lengthen to 81 characters, and warnings appear as a title mechanism (12%).

2024

Health peaks at 43% of episodes, the year the BBC described the channel as nearly half health. Credentials appear in 69% of titles, the guest's name in 66%. Warnings are the most common title shape (24%). Median episode length is 118 minutes.

2025

The second break, early April. Thumbnails become brighter and more saturated with 2.4 faces on average; black falls to 38% of the frame. Health falls back to 30% as money, AI and geopolitics grow. Shorts begin (150 this year). Median length 126 minutes.

2026

To 14 September: 74 episodes. Health 27%, science and technology 21%, society and politics 23%. Lowercase thumbnail text is down to 32%; title case is 46%. The guest's name is in 55% of titles. Fear is the highest-scoring title dimension of any year.

Three eras, detected before they were labelled

A change-point model was run across 18 measures at once to find where they shifted. It returned two boundaries: late January 2023 and early April 2025. The labels were written afterwards and describe what was measured, not intent.

Statistics

Series: topic shares, host presence, faces, thumbnail text, colour, title length and framing, packaging intensity and duration. Boundaries chosen by BIC (minimum at k = 2). Each boundary is corroborated by 14 of the 18 series on their own, and both hold when the model is re-run on the deterministic measures only.

Guest storiesOct 2020 – Jan 2023 · 158 ep.
Expert warningsJan 2023 – Mar 2025 · 222 ep.
Broader alarmsApr 2025 – Sep 2026 · 152 ep.

Guest stories

19 Oct 2020 – 23 Jan 2023 · 158 episodes

Personal development, entrepreneurship and mental health; celebrities, founders and authors; success-story and how-to titles with the guest's name in 93%; the guest alone in the frame with lowercase text; host in 27% of thumbnails; median 94 minutes.

Business episodes: 27%
Health episodes: 21%
Steven in thumbnail: 27%
Thumbnails with text: 100%
Words per thumbnail: 4.7
Packaging intensity: 30.8
Title length (chars): 72
Median length: 94 min
Median views: 464k

Top topics: Personal Development 24%, Entrepreneurship 20%, Mental Health 18%, Celebrity & Entertainment 10%, Sport 6%

Expert warnings

26 Jan 2023 – 31 Mar 2025 · 222 episodes

Health family 41% of episodes; doctors, scientists and academics; warning and revelation titles with a credential in 59%; host in 91% of thumbnails, on the right; black 49% of the frame; median 110 minutes.

Business episodes: 7%
Health episodes: 41%
Steven in thumbnail: 91%
Thumbnails with text: 99%
Words per thumbnail: 6.7
Packaging intensity: 42.7
Title length (chars): 84
Median length: 110 min
Median views: 2.5M

Top topics: Health 17%, Mental Health 12%, Relationships 8%, Psychology 8%, Money & Finance 6%

Broader alarms

3 Apr 2025 – 14 Sep 2026 · 152 episodes

Health joined by money, AI, geopolitics and society; academics and multi-guest panels; warning, hidden-truth and prediction titles; the brightest and most saturated thumbnails, 2.4 faces on average, lowercase giving way to title case; guest's name in half the titles; median 116 minutes.

Business episodes: 1%
Health episodes: 28%
Steven in thumbnail: 95%
Thumbnails with text: 100%
Words per thumbnail: 6.0
Packaging intensity: 46.7
Title length (chars): 79
Median length: 116 min
Median views: 3.4M

Top topics: Health 15%, Money & Finance 13%, Artificial Intelligence 13%, Psychology 7%, Geopolitics 7%

How the eras were detected →

What the show was about

Each episode's primary topic comes from a 25-category taxonomy applied to the title and description, grouped here into eight families. The first hypothesis tested was that the show began as a business show and became a health show. The data supports the second half but not the first.

On YouTube, business, entrepreneurship and career were never a majority: their 40-episode rolling share peaked at 42% in June 2022, and only one calendar quarter (2021 Q3) reached half. The mind family was larger in every year to 2022. Business then fell to 9% in 2023, 4% in 2024 and 1% in 2026. Health rose from 18% (2022) to 43% (2024) and has since fallen to 27% as money, AI, geopolitics and society took its place.

Share of episodes by topic family, per quarter

The mind family led until 2022; health led in 2023 and 2024; since 2025 the schedule is split between health, science and technology, and society and politics.

Periods with no classified episodes are omitted.

Business versus health, 30-episode rolling share

Business never crossed 50% in any 40-episode window; health passed it briefly in 2024 and has since fallen back below a third.

All topics in detail →

Who the guests were

Guest category comes from the title and description, with external evidence recorded for the 34 episodes the text could not settle. Founders and executives were 28 to 33% of guests in 2020 to 2022 and 13% in 2024 and 2025. Celebrities, athletes and creators were 35 to 39% in 2021 and 2022 and 5% in 2026. Doctors went from 1% (2022) to 18% (2024); scientists and academics from 2% to 31% (2026).

Titles name the guest less often and state a credential more often: the guest's name was in 92 to 95% of titles in 2021 and 2022 and 47% in 2025, while a credential (Doctor, Expert, Professor) went from 28% of titles in 2022 to 69% in 2024.

Women were 25% of interview guests and 20 to 30% in every year, with no step at either era boundary (gender from Wikidata for 378 of 449 named guests, Google panel or snippet text for 44, a model label for 18). Their share varies by subject: 8 of 10 sex-and-intimacy interviews, 24 of 62 on health, 1 of 22 on artificial intelligence.

Share of episodes by guest family, per year

Founders and celebrities gave way to doctors, scientists and academics between 2022 and 2024.

Guest family is derived from the classified guest category; every episode has one.

Guest categories and top guests →

How the thumbnails changed

Every thumbnail was measured in code: the share of pixels in each colour range, brightness, saturation, contrast, and the five largest colour clusters. No language model produced these numbers. Between the first and last 12 months of uploads, black fell from 59% to 41% of the frame, skin tones rose from 19% to 33%, brightness rose from 25 to 34 (LAB scale), and faces per thumbnail from 1.1 to 2.3.

Some measures did not change. Red pixel share fell from 20% to 16%. The red highlight box has been there since the first upload; what changed was its colour, from a mix of red, green, yellow and blue boxes in 2020–22 to red in nearly every thumbnail from 2023. Overlaid text has been on 99 to 100% of thumbnails in every year. Contrast fell as larger, evenly lit faces replaced black background.

20209 episodes

202148 episodes

202294 episodes

2023102 episodes

2024101 episodes

2025104 episodes

202674 episodes

Rows are systematic samples (every nth episode of the year). One face and lowercase text through 2022; two faces from 2023; brighter and fuller from 2025.

Every thumbnail as one colour, in order

532 episodes, oldest on the left

Each column is one thumbnail split by its largest colour clusters. Black shrinks and warm skin tones grow, most sharply from 2025.

Colour measures, 30-episode rolling mean

Black pixels (%)

White pixels (%)

Red pixels (%)

Skin-tone pixels (%)

Brightness

Saturation

Black share and brightness move in the January 2023 and April 2025 steps; red share is flat to falling throughout.

Every thumbnail measure →

Steven in the frame

The host's presence in the thumbnail is the largest single change in the study: 17% of thumbnails in the first 12 months, 94% in the last 12. Quarter by quarter the switch is precise: 32% in 2022 Q4, 60% in 2023 Q1, 77% in Q2, 100% in Q3, and never below 92% since. When present he is on the right of the frame in 97% of cases, coded serious in 54% and concerned in 28%.

The team has given two dated accounts of this change, one placing it around mid-2024 and one in the four months before April 2025. The thumbnails place it in 2023, earlier than either.

Steven in the thumbnail, 30-episode rolling share

The host went from one thumbnail in four to almost all of them between January and September 2023.

Where Steven appears (classified thumbnails)

71%

27%

Right · 71% (380)
Not present · 27% (141)
Left · 2% (9)
Centre · 0% (2)

Where present, the host is on the right of the frame 97% of the time; the guest takes the left.

Faces and expressions →

What the thumbnails say

Text has always been there: 100% of thumbnails in 2020 to 2023 carry overlaid words, 99% in 2024 and 2025, 100% in 2026. Word count rose from 4.8 to 5.7 and text dominance barely moved. The visible change is capitalisation: all-lowercase text was 77 to 100% of thumbnails from 2020 to 2024 and is 32% in 2026, with title case at 46%.

Thumbnails with any text

Words in thumbnail text

Text dominance (0–1)

Uppercase text

The amount of text is stable; the lowercase house style is being replaced in 2025 and 2026.

Thumbnail text in detail →

How the titles are written

Each title was scored 0 to 5 on eleven framing dimensions and assigned one dominant mechanism. Between the first and last 12 months, fear went from 0.6 to 1.9, authority from 1.5 to 2.5, urgency from near zero to 1.3, contrarianism from 0.4 to 1.8 and the curiosity gap from 2.1 to 2.7. The dominant mechanism moved from the success story (21% of 2021 titles, 1% of 2025 titles) to the warning (0% in 2021, 24% in every year from 2024). Titles grew from 64 to 85 characters by 2024 and have since shortened to 77.

Word counts show the same shift without a model. The terms below were selected by how much more, or less, often they appear in 2024–26 titles than in 2020–22 titles.

Title framing scores (0–5), 30-episode rolling mean

Authority

Fear

Curiosity gap

Contrarianism

Sensationalism

Title length (characters)

Fear, authority, urgency and contrarian framing all step up in 2023 and again in 2025; curiosity gap rises more gently.

Words rising and falling in titles

Occurrences per 100 titles, by publish year

Term	2020	2021	2022	2023	2024	2025	2026	Change
expert	0.0	6.3	2.1	15	23	25	28	+2.19
dr	11	2.1	2.1	6.9	16	7.7	12	+1.49
doctor	0.0	0.0	0.0	9.8	18	6.7	6.8	+3.61
truth	0.0	0.0	1.1	4.9	5.9	6.7	6.8	+1.96
if	0.0	0.0	0.0	0.0	8.9	7.7	5.4	+3.23
brain	0.0	0.0	1.1	0.0	3.0	8.7	5.4	+1.84
lying	0.0	0.0	0.0	1.0	6.9	5.8	6.8	+3.06
ai	0.0	0.0	0.0	2.0	2.0	5.8	14	+3.06
people	0.0	2.1	2.1	2.9	6.9	11	2.7	+1.21
they’re	0.0	0.0	0.0	1.0	5.9	2.9	6.8	+2.81
fat	0.0	0.0	0.0	2.9	1.0	6.7	6.8	+2.73
warning	0.0	0.0	0.0	2.0	2.0	2.9	6.8	+2.47

Founder, billion, business and story fell out of titles; expert, doctor, truth, lying and warning came in.

Shading is proportional to the cell value; the number is printed in every cell.

Statistics

Terms are ranked by the change in log-odds of a title containing the term between 2020–22 and 2024–26, smoothed; the last column shows that change.

Title mechanisms and language →

Packaging intensity

The Packaging Intensity Index is a transparent composite: the equal-weighted mean of ten measures scaled to 0–1, times 100. It describes how much a title-and-thumbnail pair uses alarm, urgency, withheld information, contrarian claims, emotional expression, high contrast and large text. It is not a judgement of the episode. Between the first and last 12 months it rose from 31 to 47, stepping up at the January 2023 boundary and again in 2025. The title half did most of the moving (16 in 2021, 41 in 2026); the thumbnail half started high and rose from 46 to 54. The index rises under every alternative weighting tested.

Packaging Intensity Index, 30-episode rolling mean

Packaging intensity rose from about 31 to about 47, in two steps that coincide with the detected era boundaries.

What goes into the index

Title: fear, urgency, negative consequence, curiosity gap, contrarianism (each 0–5, scaled to 0–1)
Thumbnail: emotional intensity, threat, urgency (0–5, scaled), contrast (0–1), text dominance (0–1)
The index is the mean of the ten components × 100. See the methodology page for the sensitivity analysis.

How the index is built →

Packaging and views

A 2021 upload has had years longer to accumulate views than a 2026 upload, so episodes are compared with their own period: relative performance is an episode's views divided by the median views of full episodes published within 90 days of it. 1.0 is typical for its period. Uploads under 60 days old are excluded.

Against that measure, geopolitics, money and science episodes and investor, scientist and psychologist guests sit above their period medians; career, entrepreneurship and sport episodes and entrepreneur and executive guests sit below. Warning and personal-threat titles run above; success stories below. Brightness has the strongest continuous relationship and black share the strongest negative one.

The largest caveat is the thumbnails themselves. Archived captures show that the biggest 2021 and 2022 episodes have been re-thumbnailed twice since publication, most recently into the current two-face design in 2025 and 2026. Their current thumbnail is not the one they earned their views with, which is why the apparent advantage of two faces over one in 2021–22 cannot be read as a packaging effect. Within a year, the relationship between face count and views is negative, and the packaging index shows no consistent within-year relationship at all.

All performance associations →

What the DOAC team has said publicly

120 short verbatim statements from 45 public sources (interviews, talks, LinkedIn posts, press) in which Steven Bartlett and members of the DOAC and FlightStory teams discuss thumbnails, titles, testing, guests and the health shift. Only the quoted words are theirs; the paraphrase is ours. The corpus records what the team says; the measurements above record what the channel did.

Method and limitations

897 public uploads were discovered from four independent listings and reconciled by video id; 532 full episodes form the core set. Thumbnails were stored and measured deterministically, then classified by a vision model under a fixed schema with one image per call and an OCR cross-check of every transcription. Titles, topics and guests were classified under fixed schemas with model id, schema version and timestamp recorded on every row. Views were normalised against nearby uploads; eras were detected statistically before labelling. The full methodology, data-quality report and dataset are published with the study.

Limitations

Classifications are model-generated under a fixed schema and versioned prompts; a random sample of ten episodes per year was reviewed by hand and the thumbnail pass was validated against OCR, which makes errors visible rather than absent.
Only current thumbnails and titles are analysed. Archived captures show the early hits were re-skinned in late 2022 and again in 2025–26, so the 2020–22 thumbnail series describes a re-skinned back catalogue, not the packaging as first published. No title history was recovered.
Views are a single-day snapshot that includes years of later discovery; relative performance controls for the period's typical level, not for an episode's later life. Every relationship with views is an association, not a cause.
Public uploads only. The podcast began in 2017, but the channel's first public episode is E53 from October 2020; earlier episodes were audio-only or have been removed.

Full methodology · Download the data · Recovered thumbnail experiments