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The Expert Scarcity Index for AI Training

On 17 Oct 2026, Chemistry was the hardest expert field to recruit for AI training work (scarcity index 1.78x, 1.00 = the market), Dutch the hardest language (1.84x) and Multilingual & Localization the hardest kind of work (1.26x); 3 groups were scarcer than the market on all three measures: applicants per opening, time to close and pay.

Data window
20 Sep 2026 to 17 Oct 2026
28 days, UTC
Computed
18 Oct 2026, 19:11 UTC
Recomputed every day
Source
The public job boards of the AI training platforms this site tracks, read every day, and the apply clicks people make on AITraining.jobs. Fields and languages are read from role titles.
Method
Version 1. Definitions
CC BY 4.0, how to cite

Every figure on this page as CSV and JSON, sent to your work email.

Key findings

  1. 1

    Chemistry is the hardest expert field to staff, with a scarcity index of 1.78x (1.00 is the market): its roles draw 0.12x the market's apply clicks per open role, its listings came down 32% less often than other roles of the same age on the same platforms, and it advertises $50/hr, 23% below the market median of $65/hr.

    Figure 1
  2. 2

    Dutch is the hardest language to staff, with a scarcity index of 1.84x (1.00 is the market): its roles draw 0.28x the market's apply clicks per open role, its listings came down 42% less often than other roles of the same age on the same platforms, and it advertises $65/hr, the market median.

    Figure 2
  3. 3

    Multilingual & Localization is the hardest kind of work to staff, with a scarcity index of 1.26x (1.00 is the market): its roles draw 0.59x the market's apply clicks per open role, its listings came down 14% less often than other roles of the same age on the same platforms, and it advertises $65/hr, the market median.

    Figure 3
  4. 4

    3 of the 43 groups with enough data are scarcer than the market on all three measures (fewer applicants per opening, slower to close than their platforms' other roles, and paid above the market): Law (1.48x), Arabic (1.29x) and Law, Medicine & Finance (1.25x).

    Figure 5
  5. 5

    At the other end, Robotics & Physical-AI Data (kind of work) is the easiest to staff, with an index of 0.51x: its roles draw 1.64x the market's apply clicks per open role, its listings came down 6% less often than other roles of the same age on the same platforms, and it advertises $10/hr, 85% below the market median of $65/hr.

    Figure 4
  6. 6

    Against their own platforms, roles in Dutch stay up longest: 12 came down where 21 would have at their platforms' pace, and its median listing lasted 25.5 days against 18 for all roles.

    Figure 4
  7. 7

    Law, the best-paid expert field with enough data ($109/hr, 1.68x the market median), draws 0.58x the market's apply clicks per open role, so its scarcity index is 1.48x.

    Figure 1
  8. 8

    43 of the 69 fields, languages and kinds of work listed have enough data on all three measures to be ranked; the rest are shown and marked as small samples.

    Figure 4

Figure 1

Scarcity by expert field

Which professions and disciplines are hardest to recruit for AI training work?

Expert fieldScarcity indexApplicant shortfallSlow closingPay premium
All roles (the market)
1.00x
1.00x1.00x1.00x
Chemistry
1.78x
5.00x1.48x0.77x
Physics & astronomy
1.66x
3.64x1.32x0.95x
Biology & life sciences
1.59x
5.00x0.80x1.00x
Engineering (non-software)
1.48x
2.59x1.25x1.00x
Law
1.48x
1.73x1.11x1.68x
Mathematics & statistics
1.18x
1.62x1.03x1.00x
Voice acting, music & sound
1.15x
1.38x0.97x1.15x
Finance, accounting & economics
1.11x
1.21x0.92x1.23x
Psychology & mental health
1.09x
1.20x0.74x1.46x
Medicine & nursing
1.05x
1.09x0.98x1.08x
Humanities & social sciences
0.97x
1.29x0.72x1.00x
Software & computer science
0.96x
0.81x1.11x1.00x
Design & visual arts
0.95x
1.02x0.77x1.08x
Business, sales & consulting
0.85x
0.74x0.82x1.00x
Writing, editing & journalism
0.66x
0.41x0.96x0.73x
Education & teachingSmall sample
0.63x
0.47x0.65x0.82x
Trust, safety & child protectionSmall sample
n/a
5.00x5.00xn/a

Sample. 17 expert fields named in the titles of roles open at the end of 17 Oct 2026; apply clicks from 20 Sep 2026 to 17 Oct 2026; listing lifetimes of the 3,542 roles listed from 3 Aug 2026 to 17 Oct 2026.

Scarcity index: the geometric mean of the three ratios beside it, each held between 0.20 and 5.00 so one extreme reading cannot decide it alone. 1.00 is the average role; above 1, harder to staff.

Applicant shortfall: the apply clicks the group's roles would have drawn at the market's rate per open role, over the clicks they drew from 20 Sep 2026 to 17 Oct 2026 (one over the demand index). Above 1, fewer applicants per opening than the market.

Slow closing: the removals expected if each of the group's roles listed from 3 Aug 2026 to 17 Oct 2026 had come down at its own platform's pace for a role of the same age (its Kaplan-Meier hazard), over the removals seen by the end of 17 Oct 2026. Above 1, its roles stay up longer than other roles on the same platforms. It is read against the same platforms because how long a listing stays up depends first on how its platform posts.

Pay premium: the median advertised hourly rate of the group's roles open at the end of 17 Oct 2026 over the median of every open role stating one ($65/hr).

A row is ranked only when its roles would have drawn at least 30 clicks at the market's rate, at least 10 removals were expected, at least 8 of its open roles state an hourly rate and at least 10 are open; otherwise it is marked as a small sample. A ratio capped at 5.00 means no click, or no removal, was recorded.

A role counts for an expert field when its title names it (whole words, the vocabulary of the expert fields report), and counts for each one it names. Titles that name none are not counted.

Source. AITraining.jobs Research, The Expert Scarcity Index for AI Training, live data.

Figure 2

Scarcity by language

Which languages are hardest to recruit for AI training work?

LanguageScarcity indexApplicant shortfallSlow closingPay premium
All roles (the market)
1.00x
1.00x1.00x1.00x
Dutch
1.84x
3.60x1.73x1.00x
German
1.70x
2.89x1.71x1.00x
Italian
1.36x
2.03x1.25x1.00x
Arabic
1.29x
1.37x1.01x1.54x
Thai
1.23x
2.85x1.45x0.45x
Korean
1.18x
1.98x0.82x1.00x
Swedish
1.09x
2.87x0.45x1.00x
French
1.09x
2.71x0.62x0.77x
Portuguese
1.02x
0.93x1.15x1.00x
Japanese
0.97x
0.91x1.02x1.00x
Spanish
0.91x
0.86x1.09x0.79x
Russian
0.85x
1.01x1.07x0.56x
Chinese (Mandarin)
0.74x
0.78x0.97x0.54x
Hindi
0.72x
0.76x0.89x0.56x
English
0.69x
0.58x1.20x0.46x
Vietnamese
0.67x
0.63x1.12x0.42x
FinnishSmall sample
2.21x
4.35x1.61x1.54x
DanishSmall sample
1.90x
5.00x0.90x1.54x
NorwegianSmall sample
1.57x
3.29x1.40x0.85x
PolishSmall sample
1.54x
2.88x0.83x1.54x
HebrewSmall sample
1.50x
1.15x1.92x1.54x
HungarianSmall sample
1.46x
5.00x1.24x0.50x
PunjabiSmall sample
1.41x
2.51x2.91x0.38x
CroatianSmall sample
1.36x
5.00x1.20x0.42x
CatalanSmall sample
1.24x
5.00x0.97x0.39x
CzechSmall sample
1.06x
2.79x0.92x0.46x
MarathiSmall sample
1.05x
2.56x0.98x0.46x
TeluguSmall sample
1.01x
1.47x2.26x0.31x
Filipino (Tagalog)Small sample
0.92x
2.37x0.59x0.56x
TamilSmall sample
0.91x
1.07x1.91x0.37x
MalaySmall sample
0.86x
2.87x0.53x0.42x
TurkishSmall sample
0.79x
1.09x1.01x0.45x
GujaratiSmall sample
0.79x
1.76x0.89x0.31x
BengaliSmall sample
0.77x
0.99x1.32x0.35x
IndonesianSmall sample
0.65x
0.76x0.64x0.56x
RomanianSmall sample
n/a
3.18x1.08xn/a
UkrainianSmall sample
n/a
2.43x0.69xn/a
UrduSmall sample
n/a
0.73x0.87xn/a
BulgarianSmall sample
n/a
1.78x1.40xn/a
CantoneseSmall sample
n/a
3.09x2.31xn/a

Sample. 40 languages named in the titles of roles open at the end of 17 Oct 2026 (the 40 with the most open roles); apply clicks from 20 Sep 2026 to 17 Oct 2026; listing lifetimes of the 3,542 roles listed from 3 Aug 2026 to 17 Oct 2026.

Scarcity index: the geometric mean of the three ratios beside it, each held between 0.20 and 5.00 so one extreme reading cannot decide it alone. 1.00 is the average role; above 1, harder to staff.

Applicant shortfall: the apply clicks the group's roles would have drawn at the market's rate per open role, over the clicks they drew from 20 Sep 2026 to 17 Oct 2026 (one over the demand index). Above 1, fewer applicants per opening than the market.

Slow closing: the removals expected if each of the group's roles listed from 3 Aug 2026 to 17 Oct 2026 had come down at its own platform's pace for a role of the same age (its Kaplan-Meier hazard), over the removals seen by the end of 17 Oct 2026. Above 1, its roles stay up longer than other roles on the same platforms. It is read against the same platforms because how long a listing stays up depends first on how its platform posts.

Pay premium: the median advertised hourly rate of the group's roles open at the end of 17 Oct 2026 over the median of every open role stating one ($65/hr).

A row is ranked only when its roles would have drawn at least 30 clicks at the market's rate, at least 10 removals were expected, at least 8 of its open roles state an hourly rate and at least 10 are open; otherwise it is marked as a small sample. A ratio capped at 5.00 means no click, or no removal, was recorded.

A role counts for a language when its title names it (whole words, the vocabulary of the languages report), and counts for each one it names. Titles that name none are not counted.

Visitors are shown the roles open in their country first, which lowers the clicks on roles limited to a few countries, as many language roles are.

Source. AITraining.jobs Research, The Expert Scarcity Index for AI Training, live data.

Figure 3

Scarcity by kind of work

Which kinds of AI training work are hardest to staff?

Sample. 12 kinds of work with roles open at the end of 17 Oct 2026; apply clicks from 20 Sep 2026 to 17 Oct 2026; listing lifetimes of the 3,542 roles listed from 3 Aug 2026 to 17 Oct 2026.

Scarcity index: the geometric mean of the three ratios beside it, each held between 0.20 and 5.00 so one extreme reading cannot decide it alone. 1.00 is the average role; above 1, harder to staff.

Applicant shortfall: the apply clicks the group's roles would have drawn at the market's rate per open role, over the clicks they drew from 20 Sep 2026 to 17 Oct 2026 (one over the demand index). Above 1, fewer applicants per opening than the market.

Slow closing: the removals expected if each of the group's roles listed from 3 Aug 2026 to 17 Oct 2026 had come down at its own platform's pace for a role of the same age (its Kaplan-Meier hazard), over the removals seen by the end of 17 Oct 2026. Above 1, its roles stay up longer than other roles on the same platforms. It is read against the same platforms because how long a listing stays up depends first on how its platform posts.

Pay premium: the median advertised hourly rate of the group's roles open at the end of 17 Oct 2026 over the median of every open role stating one ($65/hr).

A row is ranked only when its roles would have drawn at least 30 clicks at the market's rate, at least 10 removals were expected, at least 8 of its open roles state an hourly rate and at least 10 are open; otherwise it is marked as a small sample. A ratio capped at 5.00 means no click, or no removal, was recorded.

Every role is classified into one kind of work.

Source. AITraining.jobs Research, The Expert Scarcity Index for AI Training, live data.

Figure 4

What each scarcity index is made of

What applicant interest, listing lifetime and pay lie behind each group's scarcity index?

GroupOpen on 17 Oct 2026Clicks per open role a weekMedian advertised payMedian days listedScarcity index
All roles3,6680.38$6518.01.00x
Multilingual & Localization1,0040.22$6525.51.26x
Law, Medicine & Finance1,1080.23$7020.01.25x
Math & STEM2180.23$6519.41.15x
Research Studies & Surveys340.43$10011.81.04x
Coding & Software Evaluation2840.40$6517.00.99x
Red-Teaming & AI Safety540.43$7017.20.91x
Transcription, Audio & Speech5210.45$3029.10.80x
Agentic Tasks & RL Environments640.77$508.30.76x
AI Evaluation & Rating (RLHF)1430.92$5518.00.61x
Writing & Content341.25$4911.80.57x
Data Annotation & Labeling1390.96$3012.00.51x
Robotics & Physical-AI Data650.62$109.30.51x
Chemistry730.05$5027.11.78x
Physics & astronomy730.10$6232.11.66x
Biology & life sciences730.03$6514.01.59x
Engineering (non-software)1550.15$6515.81.48x
Law870.22$10927.11.48x
Mathematics & statistics780.23$6520.01.18x
Voice acting, music & sound1160.27$7520.51.15x
Finance, accounting & economics1810.31$8019.41.11x
Psychology & mental health240.32$9513.01.09x
Medicine & nursing1640.35$7019.31.05x
Humanities & social sciences360.29$6526.80.97x
Software & computer science2800.47$6513.40.96x
Design & visual arts700.37$7014.00.95x
Business, sales & consulting1100.51$6518.00.85x
Writing, editing & journalism890.93$4820.00.66x
Education & teachingSmall sample310.80$5327.00.63x
Trust, safety & child protectionSmall sample150.05n/an/an/a
Dutch540.11$6525.51.84x
German1070.13$6524.51.70x
Italian610.19$6515.51.36x
Arabic1000.28$10021.01.29x
Thai180.13$3025.51.23x
Korean690.19$6512.01.18x
Swedish340.13$65n/a1.09x
French800.14$509.51.09x
Portuguese750.41$6525.51.02x
Japanese670.42$6520.00.97x
Spanish1090.44$5127.00.91x
Russian220.37$37n/a0.85x
Chinese (Mandarin)690.49$3516.30.74x
Hindi290.50$3725.50.72x
English1630.65$3048.00.69x
Vietnamese270.60$28n/a0.67x
FinnishSmall sample280.09$100n/a2.21x
DanishSmall sample290.04$100n/a1.90x
NorwegianSmall sample150.11$5527.51.57x
PolishSmall sample350.13$100n/a1.54x
HebrewSmall sample350.33$100n/a1.50x
HungarianSmall sample120.02$33n/a1.46x
PunjabiSmall sample140.15$25n/a1.41x
CroatianSmall sample110.06$27n/a1.36x
CatalanSmall sample100.05$26n/a1.24x
CzechSmall sample150.14$30n/a1.06x
MarathiSmall sample180.15$308.01.05x
TeluguSmall sample200.26$20n/a1.01x
Filipino (Tagalog)Small sample140.16$37n/a0.92x
TamilSmall sample180.35$24n/a0.91x
MalaySmall sample120.13$28n/a0.86x
TurkishSmall sample150.35$298.00.79x
GujaratiSmall sample120.21$20n/a0.79x
BengaliSmall sample210.38$23n/a0.77x
IndonesianSmall sample240.50$3713.00.65x
RomanianSmall sample110.12n/an/an/a
UkrainianSmall sample100.16n/an/an/a
UrduSmall sample100.52n/an/an/a
BulgarianSmall sample90.21n/an/an/a
CantoneseSmall sample90.12n/an/an/a

Sample. Every group in the three scarcity tables. Open roles and pay at the end of 17 Oct 2026; new listings and apply clicks from 20 Sep 2026 to 17 Oct 2026; lifetimes and removals over the 3,542 roles listed from 3 Aug 2026 to 17 Oct 2026, back catalogues left out.

Clicks per open role a week: apply clicks on AITraining.jobs over the days the group's roles were open, times 7. Demand index: that rate over the market's (0.38).

Median days listed: the Kaplan-Meier median from the listing date to the last sighting, as in the listing-lifetime report (n/a when more than half of the group's roles are still listed at the oldest age it can be read at, or fewer than 10 were listed that long ago). It mixes how each platform posts with how fast roles fill, so the index uses the removals against the same platforms' pace instead.

Removed: roles of the cohort that came down. Expected: the removals the same roles would have had at their platforms' hazard for each age; over all roles the two are equal.

Median advertised pay: the hourly figure postings state (the middle of a stated range), shown with at least 8 roles stating one.

Source. AITraining.jobs Research, The Expert Scarcity Index for AI Training, live data.

Figure 5

Hardest to staff: scarcer than the market on every measure

Which expertise is short of applicants, slow to close and paid above the market, all at once?

GroupScarcity indexApplicant shortfallSlow closingPay premium
Law
1.48x
1.73x1.11x1.68x
Arabic
1.29x
1.37x1.01x1.54x
Law, Medicine & Finance
1.25x
1.65x1.11x1.08x

Sample. 3 of the 43 fields, languages and kinds of work with enough data on every measure, at the end of 17 Oct 2026.

Listed when all three ratios are above 1.00: fewer applicants per opening than the market, roles staying up longer than other roles on the same platforms, and a median advertised rate above the market's.

A role can count for a field, a language and a kind of work at once, so one set of roles can appear on several rows.

Source. AITraining.jobs Research, The Expert Scarcity Index for AI Training, live data.

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Method and definitions

The public job boards of the AI training platforms this site tracks, read every day, and the apply clicks people make on AITraining.jobs. Fields and languages are read from role titles. Every figure is computed by one database query over the window shown, the same query for the live report and for every edition. Each figure states its sample beneath it.

Scarcity index
The geometric mean of the applicant shortfall, the slow-closing ratio and the pay premium, each held between 0.2 and 5 so one extreme reading cannot decide it alone. 1.00 is the average AI training role; above 1, the group is harder to staff.
Applicant shortfall
The apply clicks a group's roles would have drawn at the market's rate per open role, divided by the clicks they drew in the window: one over the demand index. Above 1, fewer applicants per opening than the market.
Slow closing
For every role listed in the last 26 weeks (from 3 Aug 2026 at the earliest; back catalogues left out), the chance it comes down at each age is read from its own platform's Kaplan-Meier curve; summed over the group's roles, that gives the removals expected at its platforms' pace. Slow closing is expected removals over removals seen. Above 1, the group's roles stay listed longer than other roles of the same age on the same platforms.
Pay premium
The median advertised hourly rate of the group's open roles over the median of every open role stating one. Needs at least 8 roles stating a rate.
Median days listed
The Kaplan-Meier median from the listing date to the last sighting, as in the listing-lifetime report. Published beside the index; not part of it, because it depends first on how each platform posts.
Ranked
A group is ranked when its roles would have drawn at least 30 clicks at the market's rate, at least 10 removals were expected, at least 8 of its open roles state an hourly rate and at least 10 are open. Other groups are shown and marked as small samples.
Expert field and language
Named in a role's title, matched as whole words with the vocabularies of the expert fields and languages reports. A role naming two counts for both.
Open role
A role listed by a given day and still in its platform's feed that day.
Kind of work
Each role is classified from its title and description into one of the twelve kinds of AI training work this site tracks. Every kind links to its own page.
Window
Live: the last 28 complete days, in UTC, with listing lifetimes over every role listed in the 26 weeks to the same end (from 3 Aug 2026 at the earliest). Edition: one calendar month, with lifetimes over every role listed in the 26 weeks to its end, followed to its end.

What this data cannot tell you

  • Applicant interest is measured among the people who use AITraining.jobs, not across the market, and what is shown first gets clicked more: each visitor sees the roles open in their country first, which lowers the clicks on roles limited to a few countries, as many language roles are.
  • A listing coming down is not a hire: a role can close because it filled, because the project ended or because the platform re-posts it. Reading it against the same platforms removes each platform's posting habits, not the reasons a particular role closed.
  • Pay is what postings advertise, not what workers earn, and part of a gap between groups is where they hire: many platforms set lower rates in lower-cost countries.
  • Generic titles hide the field or language of many roles, so a group's counts are a floor; a role can count for a field, a language and a kind of work at once.
  • Platforms that recruit without a public job board are not counted.

How the job feeds are read and roles are classified: site methodology. How fresh, complete and consistent the data is, checked every day: data quality and coverage.

Editions

The live report covers the last 28 complete days and changes every day. Each complete month is also published as an edition, frozen two days after the month ends, so a figure you cite from an edition never moves.

Cite and reuse

Free to quote, chart and republish under CC BY 4.0 with a link to this page. Live figures change daily: cite a monthly edition for numbers that will read the same later, or keep the access date.

Citation

AITraining.jobs (2026). The Expert Scarcity Index for AI Training (live data, 20 Sep 2026 to 17 Oct 2026). https://www.aitraining.team/research/expert-scarcity-index (accessed 18 Oct 2026)

BibTeX

@misc{aitrainingjobs_expert_scarcity_index_live,
  author = {{AITraining.jobs}},
  title = {The Expert Scarcity Index for AI Training (live data, 20 Sep 2026 to 17 Oct 2026)},
  year = {2026},
  howpublished = {\url{https://www.aitraining.team/research/expert-scarcity-index}},
  note = {Accessed 18 Oct 2026},
}
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