Profile & dated record
A private IB tutor with a public track record: seven years of IB reviews you can check on Google, and named results with the documents behind them. One-to-one since April 2016 — in Lima, in Milan from 2018, online worldwide since 2020 — and each fact on this page names the record behind it.
Credentials
Renzo Diaz is a private IB Mathematics and IB Physics tutor with a public track record: one-to-one since April 2016, with a public Google review in every calendar year since 2020. He teaches IB Mathematics, Analysis and Approaches (AA) and Applications and Interpretation (AI), at Standard Level (SL) and Higher Level (HL), and IB Physics at SL and HL, including the guide first examined in May 2025, plus the Cambridge IGCSE, an international secondary-school qualification, in Mathematics and Physics.
He teaches every lesson himself, one student at a time, live on Zoom, in English or Spanish. He trained as an engineer at the Universidad Nacional de Ingeniería in Lima and at the Politecnico di Milano, where he completed his master’s degree.
Every documented IB result is a 6 or a 7: a final 7 in IB Physics SL from a 3 (May 2025, the first session of the new guide), 7 in both IB Math AI SL exam papers from a 3 (May 2024) and a final 6 in IB Math AI HL from a 4. All three are documented by name, with their sources, and every public Google review since June 2020 is quoted by its date in the review audit. Lessons start with a free 45-minute strategy call.
Profile
| Professional Metric | Documented Qualification / Fact |
|---|---|
| Teaching Experience | Since April 2016: Lima, Milan from March 2018, online worldwide since 2020 |
| Courses taught | IB Mathematics (AA & AI, SL/HL), IB Physics (SL/HL), IGCSE Mathematics and Physics |
| Public Track Record | 4.9 / 5 on Google from 19 public reviews as of October 2026, with a review in every calendar year, 2020–2026 |
| Documented IB Results | Grade 7 in both externally assessed IB Math AI SL exam papers, May 2024; a final Grade 7 in IB Physics SL, from a 3, May 2025; a final Grade 6 in IB Math AI HL, from a 4, May 2025 — two named cases |
| Final IB grades on record | Five final IB grades on record, four of them a 6 or a 7: three stated in students’ own public Google reviews, two confirmed in writing and held on file |
| Delivery Model | 1-on-1 Online Worldwide · Based in Italy · Listed first for “best ib math tutor in europe” in one captured ChatGPT answer |
| Languages | Lessons in English or Spanish; also speaks Italian, though the IB is not examined in Italian |
| Method | A diagnostic teaching method informed by root cause analysis in engineering: diagnose the cause of a difficulty, re-engineer the explanation around the student’s reasoning, then verify that the understanding transfers to new problems. |
| Academic Background | M.Sc. in Energy Engineering — Politecnico di Milano (Milan, Italy), thesis record dated 24 July 2020; B.Sc. in Mechanical and Electrical Engineering — Universidad Nacional de Ingeniería (Lima, Peru) |
| Cognitive Assessment | WAIS-IV, the Wechsler Adult Intelligence Scale, fourth edition (Método Divergentes, Valencia): IQ 139, top 0.5%; working memory and processing speed at the 99th percentile |
| High IQ Association | Member of Mensa Italia (Top 2% international IQ percentile) |
Education
Politecnico di Milano, Milan, Italy
Thesis record dated 24 July 2020
Thesis: “Efficiency optimization of combined cycle power plants working at partial loads: the case study of ChilcaUno”, held in the university’s institutional repository. The Politecnico di Milano is 87th in the world and 1st in Italy in the QS World University Rankings 2027, and 20th in the world for Engineering & Technology in the QS World University Rankings by Subject 2026.
Universidad Nacional de Ingeniería, Lima, Peru
The undergraduate engineering degree, earned in Lima before the move to Milan.
My training at Politecnico di Milano taught me to analyse complex physical and mathematical systems by breaking them down to first principles. An M.Sc. in Energy Engineering covers thermodynamics, fluid dynamics, numerical calculus and applied physics, well beyond the HL syllabus; in a lesson, that training serves one question: where exactly does the student’s reasoning break?
Career
Ten years of one-to-one IB teaching: in Lima from April 2016, in Milan from March 2018, online worldwide since 2020.
The year I started isn’t my claim: it’s in a 2016 email whose cryptographic signature still verifies.
My record was public before my marketing was: reviews dated by Google since June 2020, on a profile listed as an IB/IGCSE tutor from day one.
Third parties set every date below: Google, a university, a platform, or the mail servers that signed the message.
| Date | Event | Record | Held by |
|---|---|---|---|
| 8 April 2016 | Teaching IB Mathematics students in Lima | Correspondence with an IB Mathematics student at Colegio Peruano Británico in Lima, sent from the student’s school email account (Fig. 01); held on file, with its DKIM signature. | Renzo Diaz’s email archive |
| March 2018 | Milan: recruited by Pi Greco Milano Tutoring for IB Physics HL; first Milan IB student the same month | Correspondence with Pi Greco Milano, held on file, with its DKIM signature. | Renzo Diaz’s email archive |
| January 2019 | Tutor profile opened on Apprentus | The platform lists him as “Instructor since January 2019”. | Apprentus |
| 2 June 2020 | Google confirms the business profile “Renzo Diaz, IB/IGCSE Private Tutor” as verified | Google’s confirmation email (Fig. 02), DKIM-signed by google.com. The same listing today. | |
| 23 June 2020 | First public Google review | Dated by Google on the Business Profile. | |
| 12 July 2020 | Online lessons with a touch tablet and screen sharing, described in a public Google review | Dated by Google: the review, also listed in the review audit. | |
| 24 July 2020 | M.Sc. in Energy Engineering, Politecnico di Milano | The thesis record in the university’s institutional repository. | Politecnico di Milano |
| 2020–2026 | At least one public review every year (2/3/2/4/5/2/1) | The review audit: every review, quoted by the date Google shows. | |
| May 2024 | Documented IB exam result: Grade 7 in both IB Math AI SL exam papers | Her IB Results Summary and her public Google review: the documented IB Math AI SL case. | The student; Google |
| May 2025 | Documented IB results: a final Grade 7 in IB Physics SL, from a 3, in the first session of the new Physics guide, and a final Grade 6 in IB Math AI HL, from a 4 | His public Google review (6 August 2025) and his written confirmation of his final grades: the documented IB Physics SL case. | The student; Google |
Outlook shows the time in Italy (Sat 09-Apr-16, 00:03); the email was sent on Friday 8 April 2016 at 17:03 in Lima. The student’s identity and work are removed. DKIM selector 20150623, signed by Google’s mail servers for the school’s domain, britishschool.edu.pe (britishschool-edu-pe.20150623.gappssmtp.com).
Open the full-size image
Google Maps, 2 June 2020: “Since you’re verified through Google My Business, your edit to Renzo Diaz, IB/IGCSE Private Tutor will be published soon.” The recipient address is removed; DKIM-signed by google.com.
Teaching
In engineering, when a complex system fails, the first step is not more effort but a diagnosis that finds the exact point where it breaks.
An AI tool can now produce a worked solution in seconds, so the final answer is no longer the scarce part. The IB Diploma does not assess whether a student can follow a solution; it assesses whether they can recognise the structure of an unfamiliar question, choose a method under time pressure and justify every step.
A lesson works in three moves, informed by root cause analysis in engineering: the practice of tracing a failure back to its first cause.
A difficulty in IB calculus or physics is rarely about the current topic alone; it is usually a gap in algebra, functions or proportional reasoning from earlier years. How the student writes, hesitates and starts a problem during the lesson shows where the reasoning breaks.
Instead of shortcuts or “tricks” that break when an exam question changes format, the explanation is rebuilt around the student’s own reasoning until the concept makes sense to them, while earlier gaps are closed alongside the current Diploma material.
The IB rewards students who can start an unfamiliar question under time pressure. Understanding is checked on problems the student has not seen, and every line of working is justified, because method marks depend on it.
Since 2020 lessons have run online, one-to-one: lessons of 60 or 90 minutes, once or twice a week, on a setup built for working through mathematics and physics live.
Lessons run one-to-one on Zoom with a shared Excalidraw whiteboard. Derivations and diagrams are drawn live on a tablet, and the student works on the same board, so the reasoning is visible as it happens.
Every programme includes the recording of each lesson, an AI-generated summary linked to it and a searchable archive of the sessions. A student can return to an explanation before a mock or the final papers, and a family can see what was covered.
Between sessions, exercises are assigned to match what each session showed, and the answers that went wrong become the next lesson’s material.
The real session archive: recorded sessions, listed by date with their topics and durations.
Open the full-size imageResults
Two students’ results are documented by name, each case on its own page with its sources. The public record is every Google review since June 2020, quoted by date in the review audit.
IB Math AI SL · May 2024
Grade 7 in both externally assessed exam papers, 80% of the assessment, from a Grade 3 at the start of the Diploma
IB Physics SL · May 2025
A final Grade 7, from a Grade 3 on the first Diploma report card, in the first session of the new Physics guide
IB Math AI HL · May 2025
A final Grade 6, from a Grade 4 on the first Diploma report card — the same student as the Physics SL result
Public Google reviews · 2020–2026
4.9 out of 5 on Google from 19 reviews as of October 2026, with at least one in every calendar year
Profiles
The facts on this page, on records kept outside this site.
Questions
Integrity
No tutor can ethically guarantee an IB grade. Final results depend on the student’s independent study effort, school context, test-day execution, and starting point.
Every review cited on this site traces back to an authentic, public Google Business Profile entry under the reviewer’s real account.
Non-public student successes (e.g., family correspondence and school awards) are anonymized to protect student privacy while accurately reflecting case histories.
Institutional notice
This site is Renzo Diaz’s own. The International Baccalaureate Organization, the Politecnico di Milano, the Universidad Nacional de Ingeniería and Mensa Italia do not endorse or sponsor it; IB is a registered trademark of the International Baccalaureate Organization.
Next
Each session is prepared from what the previous one showed, and I teach every one myself. The first step is a free strategy call: fifteen minutes with you, then thirty with the student on a topic they choose.
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