Senior Data Scientist

Reliable AI for real work.

I combine machine learning, software engineering, and client delivery to turn difficult problems into reliable products.

Portrait of Ziad Nawar

Research depth, delivery discipline.

I am a Senior Data Scientist with a Master's degree in Artificial Intelligence from TU Delft. My work spans machine learning, natural language processing, computer vision, and full-stack development.

At Datacation, I build AI products and help teams make better technical decisions. Earlier roles at Artefact and Grant Thornton shaped how I connect research, software, and business context.

Machine learning

NLP, computer vision, forecasting, causal inference, and reinforcement learning.

Product engineering

Production pipelines, cloud infrastructure, evaluation, monitoring, and full-stack delivery.

Technical leadership

Client discovery, project recovery, mentoring, hiring, and engineering practice.

Experience

Building and recovering production AI systems, with equal attention to modeling, engineering, and the people using them.

Sep 2024 - Present

Amsterdam Zuid, Netherlands, Hybrid

Datacation logo

Senior Data Scientist

Datacation, Full-time

Datacation is an AI and data science consultancy company.

Contributed to a small language model research program for a multi-billion-dollar consumer technology company, working alongside another data scientist through a 60-day first phase, then a follow-on 8 to 10 week phase applying reinforcement learning (GRPO, RLVR) to reasoning tasks on sub-1B parameter models.

Supported proposal and delivery work with enterprise clients across building materials, industrial automation, legal technology, and logistics, alongside account and leadership teams handling stakeholder management and go/no-go decisions.

Worked with product and leadership teams at a document intelligence platform used by law firms and private equity funds, presenting user behavior findings to the CTO, CPO, and product leads that helped shape 3 later AI initiatives.

Show 9 more contributions

Took over a stalled client automation project that had no evaluation process and conflicting rules, working with a junior colleague to rebuild the pipeline, add error analysis, and get the client relationship back on track.

Worked with a junior colleague to build a demand forecasting engine (ARIMA, SARIMA, Prophet) for a manufacturing and logistics client, modeling at daily product level to improve on a single aggregate model.

Delivered a production order recommendation and demand forecasting system using probabilistic and Poisson modeling, picking up a stalled implementation from another developer and reaching a client approved handover.

Built a working AI meeting note taker prototype in 7 days, covering speech to text, LLM summarization, and Azure deployment, reaching 65 to 75% completion in the first sprint.

Ran a prompt injection security assessment on a live LLM product ahead of full rollout, writing the mitigation report that got it approved for release.

Helped drive adoption of AI coding agents across the team, scaling to 6 agents running in parallel, and co-authored an internal maturity survey and starter kit.

Co-designed a 6-week onboarding program across technical, business, and non-technical tracks, used for 10 or more new hires across 2 offices.

Maintained the company website (Next.js, Payload CMS, MongoDB, Vercel, Azure), improving technical SEO to a 99 Lighthouse score and building a drag and drop CMS editor that replaced a paid vendor tool.

Took part in 30 or more technical interviews and mentored 3 junior and medior engineers on live client projects.

Sep 2023 - Sep 2024

Utrecht, Netherlands, Hybrid

Artefact logo

Data Scientist

Artefact, Full-time

Artefact is a consultancy company specialised in AI and digital marketing.

Collaborated within a team to analyze marketing performance for a multi-billion-dollar retail client in the US market, leveraging causality analysis and time-series forecasting techniques.

Led the end-to-end development and deployment of a Bayesian-based ranking model for a popular e-sports game, including research, planning, implementation, and delivery.

Mentored an intern over a 5-week period, providing technical guidance and ensuring timely completion of an internal solution aligned with project goals and deliverables.

Nov 2020 - Sep 2023

Gouda, South Holland, Netherlands, Hybrid

Grant Thornton Netherlands logo

Software Developer

Grant Thornton Netherlands, Part-time

Grant Thornton is a global audit, tax, and advisory firm.

Collaborated with non-technical colleagues, translating business challenges into actionable technical solutions.

Delivered multiple successful full-stack projects using Outsystems, including the Tax Reporting System.

Designed and implemented a customized surveying system, enhancing workflows.

Developed systems for financial document parsing and invoice generation automation.

May 2020 - July 2020

Netherlands, Remote

ScenWise logo

Software Developer

ScenWise, Internship

ScenWise is a software development company works in the mobility sector.

Contributed to a traffic data analysis web application back-end using Java, REST API, Spring framework, and database technologies.

Selected delivery work

Difficult projects, made tractable.

Two examples of recovering inherited systems, building evaluation into delivery, and earning client confidence.

Abstract arrangement of blue threads passing through a structured system

NLP / Error Analysis / Evaluation Design

Rescuing a Stalled Client Automation Project

Logistics and document processing client
Data Scientist, paired with a junior/medior colleague

Took over a project with no evaluation process and conflicting business rules, rebuilt the pipeline from first principles, and turned an at-risk client relationship into a client-approved improvement roadmap.

Read full case study

Problem

No evaluation process existed when we took over the project.

Business rules were conflicting and inconsistently implemented across the existing pipeline.

The root cause traced back to unclear scoping and information gaps at the start of the engagement.

The client had lost confidence in the roadmap and needed a credible path forward.

Process

Paired with a junior/medior colleague to re-scope the problem from first principles rather than patching what existed.

Rebuilt the workflow end to end, replacing ad hoc fixes with a structured pipeline.

Introduced a dedicated evaluation module where none had existed before.

Ran case-by-case error analysis on a sample of production output to categorize failure modes.

Built a prioritized fix roadmap and presented it back to the client.

Solution

New pipeline architecture with clear evaluation checkpoints at each stage.

Error analysis broken down per case rather than a single aggregate accuracy number.

A documented, phased improvement plan communicated directly to the client.

Results

Reopened a transparent status conversation with the client after a period of low confidence.

Delivered a concrete, prioritized roadmap that replaced reactive, ad hoc fixes.

Established an evaluation process the team has since reused on other legacy engagements.

Learnings

Problem understanding has to happen before modeling starts, not after.

An evaluation framework is not optional overhead. It is what makes iteration possible at all.

Pairing a junior colleague on the rebuild doubled as an informal mentoring track.

Probabilistic Modeling / Azure / Data Pipelines

Building a Next-Purchase Prediction System from an Inherited Codebase

Wholesale distribution client
Data Scientist, owning the modeling workstream in a small team

Took over a three-part system from a previous developer's inherited codebase and delivered a production system that predicts customer reorder behavior, approved by the client for use in their own operations.

Read full case study

Problem

The prior developer had left inconsistent, hard-to-maintain code across the pipeline.

No monitoring existed to catch data or model issues before they reached the client.

The business need was to predict which customers were likely to reorder, and roughly when, so the client's sales team could act on it proactively.

Process

Split the system into three workstreams: database schema and ingestion from XML source data, the prediction model, and the cloud infrastructure.

Modeled repeat-purchase behavior with a probabilistic, Poisson-based approach instead of a black-box model, to keep outputs interpretable for the client's sales team.

Added monitoring across the pipeline to catch data and model issues early.

Ran an internal testing phase before any recommendation reached the client.

Kept the client in the loop with regular follow-ups to check outputs against real purchasing patterns.

Solution

A production system spanning ingestion, modeling, and Azure infrastructure.

Interpretable next-purchase predictions surfaced directly to the client's team.

Monitoring in place to catch issues before they affected client-facing output.

Results

Client approved the recommendations for use in their own systems.

Established an ongoing feedback loop for the client to validate outputs against real outcomes.

Replaced an unmaintainable inherited codebase with a system the team can extend going forward.

Learnings

An interpretable, Poisson-based model built more client trust than a more complex black-box approach would have.

Monitoring from day one avoided repeating the previous developer's maintenance problems.

Splitting the rebuild into three clear workstreams made a messy handover tractable.

Projects

Academic and independent work across language, retrieval, conversational systems, visualization, and product development.

Enhancing Clickbait Detection with Modern NLP Techniques

Advanced NLP project focusing on detecting clickbait content using state-of-the-art techniques.

Information Retrieval Model Evaluation and Improvement

Comprehensive evaluation and enhancement of information retrieval systems.

Conversational Furhat bot

Interactive conversational AI bot using the Furhat robot platform.

Multi-label Classification using Pattern Exploiting Training

Machine learning project implementing pattern exploiting training for multi-label classification tasks.

Understanding IMDb Scores through Visualization and Data Analysis

Data analysis and visualization project exploring patterns in IMDb movie ratings.

Bubble Spinner

Interactive game development project.

Green Streak

Environmental tracking application.

Research

Human-centered methods for diagnosing machine-learning systems and improving human-AI collaboration.

2023

A System for Model Diagnosis centered around Human Computation

Ziad Nawar, A.M.A Balayn, L. Corti, J. Yang

This thesis addresses the issue of reliability in machine learning (ML) systems used for computer vision applications, which can fail when faced with slightly different data than their training set. The author proposes a system to help ML practitioners debug their computer vision models before deployment. The system utilizes human computation operations to identify expected model behaviors, compare them to actual model behaviors, and assess model performance.

Read abstract

The author claims that their system is the first to allow ML practitioners to define debugging goals, configure debugging sessions, and automatically generate model debugging reports. They conducted a comprehensive evaluation of the system, demonstrating its correctness, informativeness, and cost-effectiveness, even when considering potential human errors.

Despite some limitations, the work represents an important step towards assisting practitioners in debugging ML models, encouraging further optimization, and providing open access to their code for broader usage and experimentation.

View paper
2021

Sharing human mental model with an AI agent to achieve team effectiveness

Ziad Nawar, M.L. Tielman, J.H. Krijthe

The paper discusses the collaboration between humans and digital computers in various tasks, emphasizing the importance of combining artificial intelligence (AI) agents with humans to improve team effectiveness. The focus is on the human-AI agent team and the role of shared mental models in team performance. The paper aims to experimentally analyze how different shared mental models impact human-AI agent collaboration.

Read abstract

The hypothesis is that exchanging more information within the shared mental model between humans and AI agents leads to higher team performance. The paper outlines the research questions, subdivides the research problem, and describes the experimental design. It also presents results and statistical analyses, touches on ethical considerations, and provides a discussion of the experiment's outcomes and future research recommendations before concluding.

View paper

Education

TU Delft — Delft University of Technology logo

Graduate

Master of Science in Artificial Intelligence

Delft University of Technology

Undergraduate

Bachelor of Science in Computer Science

Delft University of Technology

Working toolkit

Broad enough to ship the whole system.

Machine learning

Time Series Analysis, Natural Language Processing, Computer Vision, Data Analysis, Bayesian Statistics, Deep Learning, Reinforcement Learning, Causal Inference, ML Ops, Data Engineering

Programming

Python, Java, JavaScript, SQL, C++, R

Software development

Git, Docker, Software Design, Software Testing, Full-Stack Development

Web development

HTML, CSS, React, Node.js, Flask, FastAPI, PostgreSQL, MongoDB

Platforms

Azure, Databricks, OutSystems

Collaboration

Leadership, Teamwork, Problem Solving, Communication, Time Management