§ The result
Plum leads Mercer | Mettl by 12 points.
Plum sits 12 points above Mercer | Mettl under rubric v1.0, 54 against 42, with both filed under Assessment. Plum leads 4 of the 7 criteria, including Bias Audit Transparency, while Mercer | Mettl leads 2, including Post-Market Monitoring, and 1 is level. Bias Audit Transparency is both the widest raw gap and the heaviest weighted swing — Mercer | Mettl 42, Plum 83 — and at an 18% weight it carries 56% of the weighted advantage Plum holds across the 4 criteria on that side of the table.
Vendor profile
Mercer | Mettl
Mercer | Mettl is an online talent assessment and remote-proctoring platform offering psychometric, aptitude, coding, and skills tests plus AI-assisted exam proctoring and scoring for hiring, certification, and L&D.
Vendor profile
Plum
Plum is a pre-employment talent assessment platform that uses a Five-Factor (Big Five) psychometric Discovery Survey and a Talent Match model to score and rank candidates on behavioral "durable skills" for role fit, hiring, and development.
§ The record
Mercer | Mettl and Plum are both filed under Assessment AI. They also share 1 secondary category: Screening.
Both are in scope of NYC LL 144, Illinois HB 3773, EU AI Act, Colorado AI Act and Mobley v. Workday.
| Record | Mercer | Mettl | Plum |
|---|---|---|
| Price tier | Mid | Mid |
| Headquarters | IN | CA |
| Founded | 2010 | 2012 |
§ What decides it
The criteria that move the gap, heaviest swing first.
18% weight · 55% of the movement so far
Bias Audit Transparency
Mercer | Mettl 42 · Plum 83
7.4 weighted points to Plum
20% weight · 84% of the movement so far
Article 11 Technical Documentation
Mercer | Mettl 38 · Plum 58
4.0 weighted points to Plum
8% weight · 91% of the movement so far
Customer Documentation
Mercer | Mettl 52 · Plum 63
0.9 weighted points to Plum
12% weight · 97% of the movement so far
Human Oversight Design
Mercer | Mettl 45 · Plum 52
0.8 weighted points to Plum
12% weight · 99% of the movement so far
Post-Market Monitoring
Mercer | Mettl 38 · Plum 36
0.2 weighted points to Mercer | Mettl
15% weight · 100% of the movement so far
Data Governance Disclosure
Mercer | Mettl 55 · Plum 54
0.1 weighted points to Mercer | Mettl
Weighted delta is the raw difference times the criterion weight, so the 6 figures above sum to -12.7 — the difference between the two totals before either is rounded. Shares are of 13.5 points of movement counted without direction. The table below rounds each side to a whole number first, so its Δ raw total reads -12 beside that -12.7.
§ Category-by-category
Raw score per criterion, with weighted delta.
Δ is Mercer | Mettl minus Plum.
| Category | Weight | Mercer | Mettl | Plum | Δ raw | Δ weighted |
|---|---|---|---|---|---|
| Article 11 Technical Documentation | 20% | 38 | 58 | -20 | -4.0 |
| Bias Audit Transparency | 18% | 42 | 83 | -41 | -7.4 |
| FRIA Support | 15% | 28 | 28 | - | - |
| Data Governance Disclosure | 15% | 55 | 54 | +1 | +0.1 |
| Human Oversight Design | 12% | 45 | 52 | -7 | -0.8 |
| Post-Market Monitoring | 12% | 38 | 36 | +2 | +0.2 |
| Customer Documentation | 8% | 52 | 63 | -11 | -0.9 |
| Total | 100% | 42 (F) | 54 (F) | -12 | -12.7 |
§ Evidence
Cited sources and documented absences, criterion by criterion.
An absence is a finding, not a blank: the reviewer looked for a named artefact and recorded that it is not located. Where a source sits is a fact about hosting only.
| Criterion | Weight | Mercer | Mettl | Plum | ||||
|---|---|---|---|---|---|---|---|
| Cited | Absences | Audit / hosting | Cited | Absences | Audit / hosting | ||
| Article 11 Technical Documentation | 20% | 2 | 1 | Sources on the vendor's own domain | 3 | 0 | Sources on the vendor's own domain |
| Bias Audit Transparency | 18% | 0 | 1 | — | 3 | 0 | Audit reportSources on the vendor's own domain |
| FRIA Support | 15% | 1 | 1 | — | 0 | 1 | — |
| Data Governance Disclosure | 15% | 2 | 0 | Sources on the vendor's own domain | 2 | 1 | Sources on the vendor's own domain |
| Human Oversight Design | 12% | 2 | 0 | Sources on the vendor's own domain | 2 | 1 | Audit reportSources on the vendor's own domain |
| Post-Market Monitoring | 12% | 1 | 1 | Sources on the vendor's own domain | 2 | 1 | Sources on the vendor's own domain |
| Customer Documentation | 8% | 1 | 1 | Sources on the vendor's own domain | 3 | 0 | Sources on the vendor's own domain |
| All criteria | 100% | 9 | 5 | Sources on the vendor's own domain | 15 | 4 | Audit reportSources on the vendor's own domain |
Mercer | Mettl has 14 evidence rows across 7 of 7 criteria — 9 with a source URL, 5 documented absences; Plum has 19 evidence rows across 7 of 7 criteria — 15 with a source URL, 4 documented absences.
Provenance
The scores above are documented by 33 evidence rows on file for these two vendors: 14 for Mercer | Mettl, across 2 distinct source domains, and 19 for Plum, across 1 distinct source domain.
- Rubric
- v1.0
- Mercer | Mettl last reviewed
- June 7, 2026 · HireAIScore editorial team
- Plum last reviewed
- June 7, 2026 · HireAIScore editorial team
HireAIScore scores are editorial research, not legal advice, and no vendor pays for placement, scoring or removal — see the methodology, conflicts policy and terms.
§ Where next