Mercer | Mettl integration for Greenhouse: automate assessments, proctoring, and auto-grading
Titus Juenemann •
August 28, 2025
TL;DR
The Mercer | Mettl integration for Greenhouse streamlines skills-based screening by automating assessment invites, centralizing score data in the ATS, and offering proctoring and auto-grading for technical tests. Organizations that hire at scale, recruit technical talent, or need audit-ready assessment data benefit most; best practices include piloting for key roles, defining score-based decision rules, and tracking completion and conversion metrics. Implementations typically range from two weeks for pilots to several months for enterprise rollouts; monitor predictive validity and candidate experience to maximize ROI. For faster resume-to-assessment workflows and higher shortlist accuracy, consider adding ZYTHR to automate resume screening alongside Mettl assessments.
Mercer | Mettl's integration with Greenhouse connects interview workflows and applicant tracking data to a library of research-backed assessments, automated proctoring, and role-specific simulators. The combination reduces manual invites, centralizes candidate results inside the ATS, and allows recruiting teams to evaluate skills and cognitive fit before moving candidates to later stages. This article explains exactly how the integration works, which teams benefit the most, and the practical steps and KPIs to track during and after implementation. Expect implementation timelines, reporting use cases, common pitfalls, and best practices to maximize hiring accuracy and throughput.
At a high level, the integration automates assessment invites from Greenhouse, maps assessment scores into candidate profiles, and surfaces assessment-based hiring decisions alongside resumes and interview feedback. It supports psychometric, cognitive, coding, domain, and communication assessments, and includes AI-enabled proctoring and auto-grading for technical tests.
Core capabilities of the Mercer | Mettl — Greenhouse integration
- Automated invite and scheduling Create an assessment task in Greenhouse and Mettl automatically sends the candidate the right test with time limits, reminders, and proctoring settings applied.
- Score synchronization Assessment scores, sub-scores, and standardized percentiles are pushed back into candidate profiles in Greenhouse for unbiased comparison.
- Role templates Pre-built role-based assessment bundles (e.g., software engineer, sales, finance) speed up configuration and ensure consistent measurement across hires.
- Auto-proctoring and record-and-review AI and human proctoring flags suspicious behaviour and attaches evidence to results so hiring teams can validate test integrity.
- Language and region support Assessments are available in multiple languages and configured to account for regional compliance and accessibility needs.
AI resume screener for Greenhouse
ZYTHR scores every applicant automatically and surfaces the strongest candidates based on your criteria.
- Automatically screens every inbound applicant.
- See clear scores and reasons for each candidate.
- Supports recruiter judgment instead of replacing it.
- Creates a shortlist so teams spend time where it matters.
| Name | Score | Stage |
|---|---|---|
| Oliver Elderberry |
9
|
Recruiter Screen |
| Isabella Honeydew |
8
|
Recruiter Screen |
| Cher Cherry |
7
|
Recruiter Screen |
| Sophia Date |
4
|
Not a fit |
| Emma Banana |
3
|
Not a fit |
| Liam Plum |
2
|
Not a fit |
Who benefits most from this integration
- High-volume hiring teams Recruiters filling large numbers of similar roles gain throughput by filtering candidates with objective assessments before interviews.
- Technical hiring for engineering and data roles Auto-graded coding simulators and large question libraries reduce time-to-interview for top technical talent.
- Enterprise talent acquisition Enterprises needing structured, audit-ready assessment data inside their ATS for compliance or talent mobility benefit from integrated reporting.
- Learning and development owners Talent management teams can use pre-hire and internal assessment results to design skill development pipelines.
- Educational institutions and training partners Remote proctoring and secure exam delivery make it easier to assess and certify candidates at scale.
Typical data flow and touchpoints
| Greenhouse action | Mercer | Mettl response |
|---|---|
| Create candidate and move to assessment stage | Mettl receives trigger and sends the specific assessment link with configured proctoring |
| Candidate completes assessment | Scores, flags, and artifacts are stored in Mettl and a summary payload is posted to Greenhouse |
| Recruiter views candidate profile | Assessment scores and recommended actions appear as custom fields and attachments in Greenhouse |
| Hiring manager requests deeper analysis | Detailed reports and simulators are accessible via Mettl links included in the candidate record |
Candidate experience is important to adoption. With the integration, candidates receive single-click assessment links and contextual instructions based on their role. Proctoring options vary by test complexity — quick cognitive screens use auto-proctoring while high-stakes certifications use live or record-and-review proctoring.
Assessment types included and practical use-cases
- Psychometric and behavioral tests Use these to predict cultural fit and behavioral tendencies relevant to a role, such as risk orientation or teamwork propensity.
- Cognitive ability tests Short aptitude screens to triage large candidate pools or confirm problem-solving ability before technical interviews.
- Coding assessments and simulators Auto-graded coding problems and end-to-end simulators for front-end, back-end, full-stack, data, and DevOps roles.
- Domain and functional assessments Role-specific assessments for sales, finance, HR, and industry-specific knowledge checks.
- Communication and language tests AI-powered speech evaluation and writing assessments for customer-facing roles and international hires.
Setting up the integration typically involves admin-level access in Greenhouse, an API key exchange, and mapping assessment templates to Greenhouse job stages. Create standardized job templates first, then link Mettl assessment bundles. Test with a pilot job and a small group of candidates to validate score mapping and proctoring behavior before broad rollout.
Key metrics to track after launch
| Metric | Why it matters |
|---|---|
| Time-to-hire | Shows whether assessment-driven screening speeds up or slows down the pipeline |
| Interview-to-offer ratio | A falling ratio indicates better pre-screening quality |
| Assessment completion rate | High drop-off may indicate poor candidate instructions or overly long tests |
| Pass rate by assessment and role | Helps calibrate difficulty and benchmark against historic hiring success |
| False positive/negative hires | Track hires who underperform despite passing assessments to tune test selection |
Common technical and compliance questions
Q: Do assessment scores override Greenhouse interview feedback?
A: No. Scores are recorded as structured data points and should be used alongside interviews and reference checks. Best practice is to establish score thresholds that trigger specific workflow actions rather than automatic decisions.
Q: How is candidate data privacy handled?
A: Mercer | Mettl provides region-specific data handling options and a published privacy policy. Customers should confirm data residency and consent flows during implementation.
Q: Can proctoring be disabled for certain roles or regions?
A: Yes. Proctoring options are configurable per-assessment so you can disable or change proctoring based on role sensitivity and local regulations.
A typical implementation timeline ranges from 2 to 8 weeks depending on scope. Small pilots can be configured in under two weeks, while enterprise rollouts requiring legal review, single sign-on integration, and custom assessment development may take several months. Required resources usually include a project owner in TA, an IT/API lead, and an L&D or assessment SME to validate content.
Best practices to maximize integration ROI
- Start with role-critical tests Begin by integrating assessments for 2–3 high-volume or high-impact roles to prove value and refine workflows.
- Define decision rules up front Create clear score thresholds and actions (e.g., auto-reject, move to phone screen) so recruiters apply assessments consistently.
- Monitor candidate drop-off If completion rates are low, reduce test length, improve instructions, or change timing in the workflow.
- Use analytics to recalibrate Regularly compare assessment results with performance data to adjust difficulty and predictive models.
- Train recruiters and hiring managers Provide short guides on interpreting scores, sub-scores, and proctoring flags to avoid misinterpretation.
Common pitfalls include over-testing candidates, misconfigured score mappings, and ignoring assessment evidence in hiring discussions. Practical troubleshooting steps: validate API logs during pilot, sample candidate completions to verify proctoring artifacts, and run quarterly audits of assessment predictive validity against new-hire performance.
Streamline screening with ZYTHR
If you use Mercer | Mettl with Greenhouse, add ZYTHR to your stack to automate resume screening and prioritize candidates who match both experience and assessment signals. ZYTHR speeds up resume review, reduces manual bias, and improves shortlist accuracy so you can focus interviews on the best-fit candidates.