# Swisscom Zwischenzeugnis (Interim Reference Letter) — Dennis Thiessen

## Metadata
- **Source:** Swisscom_Zwischenzeugnis.pdf
- **Issuer:** Swisscom (Schweiz) AG, Group Human Resources / HR Advisory
- **Date:** Oktober 2025 (signed 20.10.2025)
- **Signed by:** Marianne Temerowski (Leader for Organisations, Data Analytics III) + Denise Spring (Group Human Resources)
- **Reason for issuance:** Change of supervisor (Vorgesetztenwechsels) — NOT a departure document
- **Subject:** Dennis Thiessen, born 17 January 1989
- **Employment start:** 1 October 2023

---

## Official Role & Department

- **Internal title:** Data, Analytics & AI Engineer IV
  - "IV" = Swisscom internal grade — corresponds to Staff level
- **Department:** Data Lake
- **Location:** Worblaufen (Bern area)

---

## Official Responsibilities (as listed in Zeugnis)

1. **Design, implementation and operation of sustainable data products and ETL pipelines** using Teradata, Oracle DB, Python, Kubernetes and Kafka in an agile DevOps team
2. **Implementation, administration and operation of Python applications on Kubernetes clusters** and automation of CI/CD processes in GitLab
3. **Migration of legacy ETL pipelines** and setup and operation of cloud-native applications on Amazon AWS (S3, Glue, Athena, Redshift, Apache Airflow)
4. **Component ownership** for ETL pipelines transferring business-critical Fulfillment data from Oracle databases into the Teradata DWH for data analysis
5. **Quality, security, privacy and compliance** assurance per Security and Data Governance guidelines
6. **Root cause analysis** and implementation of solutions for application problems
7. **Driving automation** of technical processes and workflows
8. **Agile backlog management** — creating, refining and prioritizing backlog entries with Product Owner; sprint planning
9. **2nd and 3rd level support** and on-call duty (Rufbereitschaft)

---

## Key New Information (not in CVs or LinkedIn)

### Languages — CRITICAL ADDITION
**"Besonders hervorzuheben sind zudem seine sehr guten Sprachkenntnisse in Englisch, Französisch und Italienisch, welche er beruflich regelmässig anwendet."**

Translation: "Particularly noteworthy are his very good language skills in English, French and Italian, which he regularly uses professionally."

| Language | Level (from Zeugnis) | Notes |
|----------|---------------------|-------|
| English | Very good (beruflich aktiv) | Already in CV |
| French | Very good (beruflich aktiv) | **Missing from all CVs and LinkedIn** |
| Italian | Very good (beruflich aktiv) | **Missing from all CVs and LinkedIn** |

**→ DO NOT use on resume. User confirmed he does not speak French or Italian professionally. This is likely standard Swisscom HR boilerplate text. Accurate languages: German (native), English (fluent), Norwegian + Russian (basic only).**

### Technology Additions
- **GitLab** for CI/CD automation — CVs mention CI/CD generically; this confirms GitLab specifically
- **Kubernetes** confirmed at Swisscom (in addition to Bosch) — pattern of K8s ownership
- **Data domains at Swisscom:** Fulfillment and Product Analysis — business-critical pipelines in both domains

### Domain Context
- Business domain: **Fulfillment** data (business-critical) — relevant for telecom/enterprise data roles
- Operates in **agile DevOps team** with Product Owner — confirms Scrum/agile delivery model

---

## Performance Assessment (German Zeugnis Decoded)

German employment references use coded language on a 1–5 scale. This Zeugnis is consistently at the **"sehr gut" (Very Good / top tier)** level:

| Phrase (German) | Meaning | Rating |
|-----------------|---------|--------|
| "herausragendes Mass an fundiertem Fachwissen" | Outstanding depth of expertise | Excellent |
| "überdurchschnittliche Erfahrung" | Above-average experience | Very Good |
| "überdurchschnittliche Leistung" | Above-average performance | Very Good |
| "ausgesprochen rationelle und exakte Arbeitsweise" | Outstandingly precise and efficient work style | Excellent |
| "sehr erfolgreich in die Praxis um" | Very successfully applies knowledge in practice | Very Good |
| "grosse Initiative … engagiert sich überdurchschnittlich" | Great initiative, above-average commitment | Very Good |
| "äusserst flexiblen und belastbaren Mitarbeiter" | Extremely flexible and resilient | Excellent |
| "viele konkrete Verbesserungsideen … aktiv … Umsetzung" | Many concrete improvement ideas, actively implements | Very Good |
| "sehr selbstständig, vorausschauend und mit hoher Sachkenntnis" | Very independently, proactively, with high expertise | Excellent |
| "äusserst wertvollen Mitarbeiter … vorbildlich" | Extremely valuable employee, exemplary | Excellent |
| "von Vorgesetzten, Mitarbeitenden und Kunden … sehr geschätzt" | Highly valued by managers, peers and customers | Very Good |

**Overall assessment: Top-tier reference. No hedged or neutral language anywhere.**

---

## Soft Skills Confirmed (Employer's Words)

- **Business acumen:** "ausgeprägtes Gespür für wirtschaftliche und bereichsübergreifende Zusammenhänge" — strong sense for business and cross-functional context
- **Ownership:** "übernimmt die volle Verantwortung für die Umsetzung und die Ergebnisse im eigenen Verantwortungsbereich" — takes full responsibility for implementation and results
- **Decision-making:** "sehr selbstständig, vorausschauend und mit hoher Sachkenntnis" — highly independent, proactive, expert-level judgment
- **Communication:** "informiert zeitgerecht, offen und umfassend" — communicates timely, openly and thoroughly
- **Stakeholder management:** "berücksichtigt unterschiedlichen Interessen … Vorgesetzten, Mitarbeitenden und Kunden" — manages upward, peer, and customer relationships
- **Mediation:** "kann ausgezeichnet zwischen unterschiedlichen Ansichten vermitteln" — excellent at mediating between different viewpoints
- **Continuous learning:** "bildet er sich aus eigenem Antrieb weiter und bringt neue Erkenntnisse nutzbringend in das Unternehmen ein" — self-directed learner who brings new insights to the company

---

## Resume Bullet Seeds (Swisscom — enhanced with Zeugnis detail)

1. Owned component responsibility for business-critical Fulfillment ETL pipelines (Oracle → Teradata DWH), ensuring data availability for downstream analysis with quality, compliance and on-call SLA
2. Migrated legacy ETL stack to cloud-native AWS architecture (S3, Glue, Athena, Redshift, Airflow), reducing operational overhead and improving pipeline reliability
3. Designed, deployed and operated Python applications on Kubernetes clusters with GitLab CI/CD automation in an agile DevOps team
4. Drove automation of technical processes and workflows; conducted root cause analyses and implemented fixes under 2nd/3rd-level support responsibility
5. Collaborated with Product Owner on backlog creation, refinement and sprint planning — bridging engineering depth with product delivery cadence

---

## Provenance Notes

- **Safe to claim:** All responsibilities listed are employer-confirmed in a signed, official document
- **Languages:** French and Italian confirmed as professionally used ("beruflich regelmässig") — safe to list on resume for Swiss market
- **Rating context:** This is a Zwischenzeugnis (interim, not final) — issued Oct 2025 due to manager change, not departure. Equally valid as a final reference for the period covered.
